More than 80,000 websites including giants such as Facebook, Amazon and Google, are taking part in an online protest on Wednesday against the U.S. telecoms regulator's plan to roll back net neutrality rules.

Under the Barack Obama administration in 2015, rules were put in place that meant internet service providers (ISPs) such as Comcast, Charter, and AT&T, had to treat all internet content equally. Essentially these ISPs are not allowed to block content or speed up or slow down data from certain websites.

This principle of net neutrality came under threat in May after the U.S. Federal Communications Commission (FCC), which is headed up by Ajit Pai who was appointed by President Donald Trump, voted to reverse rules put in place under Obama.

The FCC argues that this will boost investment in new technology by removing regulation.

But internet companies have been vocal in their opposition to Pai's plans. That's why on Wednesday, many of these services are planning an online protest called the "Day of Action". Among the companies taking part are Twitter, Amazon, Facebook, Google, Reddit, Netflix, Airbnb, and Spotify.

"The FCC needs to listen to the voices of real people who will be affected by this attack on net neutrality protections – not just lobbyists from telecom companies in pursuit of more power," Evan Greer, campaign director of Fight for the Future, one of the organizations behind the protests said in a statement on Tuesday.

"The goal of the protest … is to ensure that ordinary people have a voice and are heard by decision makers in Washington, D.C. No one – regardless of their political affiliation – wants their cable company to control what they can see and do on the Internet, or to charge extra fees to access the content they want."

These sites are planning to show messages on their homepages speaking out against the FCC's plans. Signs like the one below will begin to appear on some websites urging people to send a letter to the FCC.

Twitter meanwhile has put out a blog post encouraging people to use the hashtag #NetNeutrality.

"The FCC should abandon its misguided effort to obviate all the work that has been done on behalf of all Internet users," Lauren Culbertson, public policy manager at Twitter, wrote in a blog post on Tuesday.

Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.