About 200 internet companies and activist groups are coming together this week to mobilize their users into opposing US government plans to scrap net neutrality protections.

The internet-wide day of action, scheduled for Wednesday 12 July, will see companies including Facebook, Google, Amazon, Vimeo, Spotify, Reddit and Pornhub notify their users that net neutrality – a founding principle of the open internet – is under attack. The Trump administration is trying to overturn Obama-era regulation that protected net neutrality, and there is less than a week left for people to object.

Just as the internet came together in a blackout to protest against the Stop Online Piracy Act (Sopa) in 2012, many websites will on Wednesday feature a prominent message on their homepage, showing visitors what the web would look like without net neutrality and urging them to contact Congress. But what exactly is net neutrality, why is it under threat, and what can individuals do to protect it?

What is net neutrality?

Net neutrality is the idea that internet service providers (ISPs) treat everyone’s data equally – whether that’s an email from your mother, a bank transfer or a streamed episode of The Handmaid’s Tale. It means that ISPs don’t get to choose which data is sent more quickly, and which sites get blocked or throttled (for example, slowing the delivery of a TV show because it is streamed by a video company that competes with a subsidiary of the ISP) and who has to pay extra. For this reason, some have described net neutrality as the “first amendment of the internet”.

“Net neutrality is basically the principle that keeps the internet open. Without it, big cable companies will be able to slow down certain websites and pick winners and losers on the internet,” said Mark Stanley from Demand Progress, one of the activist groups organizing the day of action.

What is the difference between an ISP and a content provider?

ISPs, such as Verizon, Comcast, Charter, Verizon, CenturyLink and Cox, provide you with access to the internet. Content companies include Netflix, Hulu and Amazon. In some cases, ISPs are also content providers: for example, Comcast owns NBCUniversal and delivers TV shows through its Xfinity internet service.

Why is net neutrality under threat?

In February 2015, the Federal Communications Commission (FCC) voted to more strictly regulate ISPs and to enshrine in law the principles of net neutrality.

The vote reclassified wireless and fixed-line broadband service providers as title II “common carriers”, a public utility-type designation that gives the FCC the ability to set rates, open up access to competitors and more closely regulate the industry.

“The internet is the most powerful and pervasive platform on the planet,” said FCC chairman Tom Wheeler at the time. “It’s simply too important to be left without rules and without a referee on the field.”

Two years on, Trump’s new FCC chairman, Ajit Pai, a former Verizon lawyer, has pushed to overturn the 2015 order. On 18 May, the FCC voted to support a new proposal that would repeal the order and started a 90-day period in which members of the public could comment. The deadline for feedback is 17 July, after which the FCC has to provide reply comments by 16 August, before a final vote later in the year.

Who supports net neutrality?

Content providers including Netflix, Apple and Google. They argue that people are already paying for connectivity and so deserve access to a quality experience.

Mozilla, the not-for-profit company behind the Firefox web browser, is a vocal supporter, and argues that net neutrality allows for creativity, innovation and economic growth.

More than 800 startups, investors and other people and organizations sent a letter to Pai that read: “Without net neutrality, the incumbents who provide access to the internet would be able to pick winners or losers in the market. They could impede traffic from our services in order to favor their own services or established competitors. Or they could impose new tolls on us, inhibiting consumer choice.”

Many consumers support the rules to protect the openness of the internet. Some of them may have been swayed by Last Week Tonight host John Oliver, who pointed out that “there are multiple examples of ISP fuckery over the years” – so restrictions are important.

Who doesn’t support the FCC’s 2015 net neutrality rules?

Big broadband companies including AT&T, Comcast, Verizon and Cox. They argue that the rules are too heavy-handed and will stifle innovation and investment in infrastructure. These firms have filed a series of lawsuits challenging the FCC’s authority to impose net neutrality rules.

Publicly, however, the message is different. Verizon released an odd video insisting that they were not trying to kill net neutrality rules and that pro-net neutrality groups are using the issue to fundraise.

Comcast also launched a Twitter campaign insisting it supported net neutrality.

Are there other reasons why people don’t like the 2015 rules?

Yes. Opponents don’t like the idea of putting the federal government at the center of the internet when, as Pai has said, “nothing is broken”.

The new FCC chairman argues that the 2015 rules were established on “hypothetical harms and hysterical prophecies of doom” and that they are generally bad for business.

“It’s basic economics. The more heavily you regulate something, the less of it you’re likely to get,” he said.

The big broadband companies publicly state they are quibbling the title II “‘common carrier’” designation rather than net neutrality per se. They believe they shouldn’t be regulated in the same way that telecommunications services are, and prefer the light-touch regulation they would otherwise be subject to under their previous title I designation of the Telecommunications Act of 1996. The FCC lacks the direct authority to regulate title I “information services”.

Who is behind the day of action on 12 July?

Fight for the Future, Free Press Action Fund and Demand Progress have teamed up to create the Battle for the Net campaign. They have signed up almost 200 participants in the day of action, and created explainer videos, banner advertisements, tools and suggested messaging for communicating with users en masse about why net neutrality matters.

How does this tie in to Trump’s approach to the internet?

Trump’s Republican party is friendly to big corporations – even if it leads to the unfettered accumulation of corporate power.

It’s the second major rollback of Obama-era internet protections. In March, Congress voted to allow ISPs to sell the browsing habits of their customers to advertisers. The move, which critics charge will fundamentally undermine consumer privacy in the US, overturned rules drawn up by the FCC that would have given people more control over their personal data. Without the rules, ISPs don’t have to get people’s consent before selling their data – including their browsing histories – to advertisers and others.

What can people do?

Tell the FCC and Congress to protect the open web through BattleForTheNet.com, or through one of the widgets on many popular websites on Wednesday.