Shares of Twitter went on sale to the public for the first time Thursday, instantly leaping more than 70 percent above their offering price in a dazzling debut that exceeded even Wall Street's lofty hopes, according to AP:

By the closing bell, the social network that reinvented global communication in 140-character bursts was valued at $31 billion nearly as much as Yahoo Inc., an Internet icon from another era, and just below Kraft Foods, the grocery conglomerate founded more than a century ago.

Twitter, which has never turned a profit in the seven years since it was founded, worked hard to temper expectations ahead of the IPO, but all that was swiftly forgotten with the stock's opening surge.

The most anticipated initial public offering of the year was carefully orchestrated to avoid the glitches and eventual letdown that surrounded Facebook's first appearance on the Nasdaq 18 months ago.

Trading on the New York Stock Exchange under the symbol "TWTR," shares opened at $45.10, 73 percent above their initial offering price.

In the first few hours, the stock jumped as high as $50.09. Most of those gains held throughout the day, with Twitterclosing at 44.90, despite a broader market decline.

As we wait to see what price Twitter closes at, here's some perspective:

"In my mind they certainly could've raised the price on this thing and gone into the low 30s," says Ken Polcari, director of the NYSE floor division at O'Neil Securities.

From an outsider looking in I would say they were overly cautious because they didn't want a disaster on their hands [...] I'm sure the company didn't want a Facebook debacle, I get that, but I think they were overly cautious and it cost them some money.

Here's the Twitter team on the floor of the New York Stock Exchange this morning. The photo was taken moments after they all got loads more money from the launch. TWTR is currently trading up at $48.15. We'll see where it is when the stock exchange closes at 4pm.

The Guardian's US finance and economics editor, Heidi Moore, wants to know your predictions for how Twitter's stock will perform over the coming weeks.

"Readers, here's your chance to try to predict a stock's level like a professional. Here's our question to you: Where do you think Twitter's stock will trade in 15, 30, and 45 days after its IPO?"

You can stick your guesses in here:

"In hindsight when you look at this you almost think they left a little too much money on the table," Roger Entner from Recon Analytics has told the Associated Press.

What Entner means, AP says, is that Twitter raised $1.8 billion Wednesday night when it sold 70 million shares at $26 each. Had it priced the stock at $30, for instance, the company would have taken away $2.1 billion. At $35, it would have reaped nearly $2.5 billion.

“Twitter’s IPO shows the sublime and ridiculous nature of our capital markets," says Peter Garnry, head of equity strategy at Saxo Bank.

Sublime because the IPO went smoothly in terms of trading, but also because it shows how the capitalist system allocates capital to growth companies. But the IPO is also ridiculous because these tech IPOs have become like a video game cheered by ordinary people and the media.

The valuation at these price levels is disconnected from any logical calculation and reflects a huge downside risk for investors if Twitter does not meet expectations at every quarterly earnings release from now on. For Twitter it is the end of a long journey towards the public market. For investors this is the beginning of nerve-racking journey of whether Twitter can deliver on the huge expectations.

Here's a graph of Twitter's performance over the first couple of hours. The bottom bar chart shows the volume of trading has dropped since the massive interest at launch:

Gemma Godfrey, who is apparently the "most popular businesswoman on Twitter", sends this summary:

Reuters has this snappy report on the Twitter IPO:

Twitter Inc soared as much as 92 percent in its first day of trading on Thursday on the New York Stock Exchange as investors snapped up shares in the popular microblogging site in a frenzy that recalled the days of the dot-com bubble. 

The shares opened at $45.10 a share, up from the initial public offering price of $26 set on Wednesday, then added to those gains, hitting a high of $50. They were up 73.7 percent to $45.15 at midday. 

Sources said the flotation drew strong demand, with investors asking for 30 times the number of shares on offer as they bet on potential growth at the money-losing social media company. 

The opening price valued the shares at about 22 times forecast 2014 sales, nearly double that multiple at social media rivals Facebook Inc and LinkedIn Corp. 

The shares opened 73 percent above the $26 initial public offering price set on Wednesday, making it the biggest in a series of huge opening day "pops" for IPOs. Including restricted share units and other securities that could be exercised in the coming months, the company's market value was over $28 billion.

So now you know:

The Guardian's Dominic Rushe has been speaking to Larry Chiagouris, professor of marketing at Pace University, who has poured more cold water on the Twitter fire.

Twitter’s entire business model is based on advertising but not on the ads it has but on the ads it hopes one day it might get. As yet we have no evidence that it will ever get those ads and at this valuation, that’s a problem.

Those savvy internet-types over at the Associated Press have put together a "glossary" of Twitter terms, because they reckon that "Twitter-specific lingo that could look like alphabet soup to the uninitiated".

I like "Egg" best:

Tweet: That 140-character message sent out on Twitter. Also, the sound a small bird makes.
Follow: Find an account you like? Click "follow" to have their tweets show up in your feed.
RT: Stands for retweet, or resubmitting someone else's tweet to your followers.
HT: Hat Tip, means you are sharing a link or idea someone else shared first, so you're giving them credit. Not quite a retweet.
DM: Direct Message, a private message sent to another user. You can send it only to people who follow you.
@: Add before someone's name to reply to them publicly. It's only shown in the feeds of those who follow both of you.
Egg: Unless you upload a profile photo, an egg will show up in its place. Often a sign of a spam account, or someone new to Twitter.

Earlier, in a fit of whimsy, I asked readers to send in their first tweets. The response has been overwhelming. Four people have replied! Each of them win a Guardian rubber eraser:

And Myles Winstone takes first prize for sheer longevity:

Some timely realism from Wired, which observes that "outside of Wall Street and Silicon Valley, it’s hard to get excited about the Twitter IPO. And few people do." The tech magazine then twists the knife by noting that "the truth is that few people here in the States actually use the thing".

Despite all the froth around Twitter’s IPO, the company isn’t all that big, with a valuation, at the moment, of around $31.5 billion. Rival Facebook clocks in at around $120 billion, while an icon of the last tech boom, Amazon, is worth $163 billion. Google is at $342 billion. Twitter is closer to being an Intuit or Adobe than the next Facebook.

Part of that difference is down to the fact that Twitter bleeds cash while Facebook gushes profit. After losing $80 million last year, Twitter posted a net loss of $134 million for the first nine months of this year, according to a company filing with the Securities and Exchange Commission. It has never been profitable. Facebook, in contrast, grew profits for at least three years to $1 billion before it went public.

But it’s not just that Twitter is small and unprofitable. The truth is that few people here in the States actually use the thing. The social network remains a niche product, beloved by journalists, celebrities, and a hard core of miscellaneous obsessive users — but few others.

Unlike Facebook, it’s not a ubiquitous online utility, and you’re not going to find grandma on there. Twitter has only 53 million monthly active users in the U.S., where it earns most of its ad dollars, as of the third quarter of this calendar year. That’s less than a quarter of its total number of users. Facebook reaches 180 million to 199 million people in the U.S.

Twitter chairman Jack Dorsey has been tweeting about the launch. Dorsey owns 23.4m shares in the company, and is reportedly planning to take his other start-up, Square, public in 2014 too.

That $45.10 opening share price is up 73% on the IPO price of $26. Twitter is trading under the symbol TWTR.

The share price values Twitter at $31.3bn, according to the Associated Press.

The Twitter trading is "absolutely stunning" given the mooted launch price a week ago was around $17-$20, says Joshua Raymond from City Index.

We knew Twitter shares would be in high demand but perhaps this still goes down as hugely impressive, and is further evidence of the hunger to invest in innovative new media types such as social media. IPO’s are of course highly volatile so whilst this would appear to be a very successful market debut for Twitter, we must take a step back and judge investor appetite over a longer period of time.

Jim Cramer is the noisy guy from CNBC/Arrested Development.

Emmett Kilduff, CEO of Eagle Alpha, a company that analyses online data, has put together a report looking at the Twitter IPO.

My colleague Dominic Rushe reports that Kilduff said the IPO looked to have been very well managed, but warned there were issues ahead. In particular Kilduff said advertisers wanted to see improvements in Twitter's ad platform and marketing.

"We were also incredibly surprised by the number of fake followers there were. Estimates suggest that Britney Spears has as many as 36%, that’s around 7 million users, yet we found few comments online by advertisers and advertising agencies complaining about this," Kilduff wrote.

Twitter CEO Dick Costolo was on CNBC this morning as the company went public.

"We're all very proud at the company of everything that we've accomplished. [...] It's been our users that have gotten us to where we have got today. But I would also say that we have a lot of work ahead of us, a lot of work to do."

"All the capital raised today is going into the company," Costolo said. Asked about new user growth in the US, which is said to be slowing and was a concern for some investors ahead of the launch, Costolo said:

We have a tremendous set of thoguhts and startegies to increase the slope of the growth curve. I would consider some of them tactics, some of them strategies. [...] There is an entire set of strategies like the onboarding experience into Twitter, from that moment you hear about it and you come to the service and sign up, to really getting it, understanding it and becoming active on the platform. [...] It's all about making it very simple and easy for new users to come to the platform, to understand what's going on on the platform, engage with content easily and immediately on the platform.

Thanks to Matthew Keys for the audio.

The scene down at Wall Street:

"Before the dancing bears start invading the New York Stock Exchange and strolling jugglers on stilts whirl us up into this particular capitalist circus, maybe it's a good time to stand back and put the Twitter IPO in perspective," writes Guardian US finance editor Heidi Moore.

For one thing, let's take that size: $1.8 billion. Yes, that makes it the biggest tech IPO since Facebook, but that's like comparing Earth to Jupiter. The Facebook IPO was $16 billion, which is many, many little Twitters. The Google IPO, at $1.9 billion, was also bigger. Twitter is not the biggest IPO of all time; it's not even the biggest IPO of 2013. According to Thomson Reuters, the Twitter debut is the seventh-largest IPO this year. 

There are also key questions about whether Twitter should be worth that much. At these prices, the company is worth 33 times its sales. That's remarkable because Twitter's active users number about 232 million, while Facebook, with one billion active users, has stock that trades at about half that, or 17 times sales. Google, which we all acknowledge as our Internet overlord, has shares that go for only five times sales. 

The Twitter IPO is not a capitalist rave. No one will make money except the founders and some people who are already millionaires. So let's all pace ourselves.

According to CNBC, citing "initial reports", Twitter is trading at around $44-45 per share after opening at $26. We're waiting for an official price.

We're waiting to hear the price Twitter is trading at. CNBC has live, breathless coverage from the floor of the New York Stocjk Exchange, if that's your thing.

In the meantime, here is the first ever tweet by Twitter co-founder Jack Dorsey:

And hey! Here's my first tweet:

Send me your first Twitter post if you like, @adamgabbatt. (p.s. Buzzfeed has this explainer on how to find your first tweet.)

The fact that Twitter is selling its shares doesn't mean any old pleb can go and buy a slice of the company. Even savvy investors like me, with my 124 shares in BT Group PLC, will have to wait to add to our portfolios.

The vast majority of shares are sold to mutual funds and investment bankers and that sort of thing, according to USA Today.

The Guardian's Heidi Moore explains everything about the Twitter IPO here.

Hurrah! Twitter is now public! And Sir Patrick Stewart was the one to peal the bell!

The official @Twitter has also tweeted about the Twitter launch. A Twitter user might describe this as "meta" and they might also write "lol":

One of the fears for Twitter's founders and investors is that today's debut mirrors Facebook's IPO last May. That sale "proved a disaster", writes my colleague Dominic Rushe:

Facebook sold its shares at $38 – the top end of the range it had set – and found that long-term investors were not keen to hold the stock after reports that the company was struggling to make money from mobile advertising. Shares slumped shortly after the IPO and it took a year for the shares to pass the price they launched at. But pricing Twitter's offer too low would reduce the money the company could raise.

Before the pricing, Tomas Freyman, director of valuations at BDO, worried that history was about to repeat itself. "Despite Twitter's price range valuing being more modest than some of the numbers bandied about over the last few weeks, this is still very high for a company that has yet to make any profits," he said. "Value in Twitter is being largely driven by the hype surrounding the brand and the recent successes of other online businesses including Google, LinkedIn and Facebook, despite the latter's early wobbles.

Twitter is going public at 9.30am. The technology company will be listed on the New York Stock Exchange, and the company will be selling 70m shares at a price of $26 per share.

The $26-per-share pricing gives the company – which has not made a profit for the last three years – a value of $14.2bn.

The launch will net hundreds and hundreds of millions for some lucky Silicon Valley investors. Co-founder Evan Williams is due to make $1.47bn from the sale. Fellow co-founder Jack Dorsey could make around half that. Other backers including Amazon founder and Washington Post-rescuer Jeff Bezos could also rake in small fortunes to add to their already large ones.

Twitter made its first public financial statement last month ahead of the big launch. It showed that it lost $79.4m in 2012 and was on track to lose even more in 2013.

Those losses are not expected to deter investors from clamouring for a piece of Twitter today, however. Despite its poor financial performance Twitter has promising mobile stats and is set to turn a profit in 2015.

How will Twitter fare? Will its share price soar above $26? Or drop below? Or neither? Follow live coverage of all the furore here.