The Federal Communications Commission's repeal of net neutrality rules, which had required internet service providers to offer equal access to all web content, took effect Monday.

The rules, enacted in 2015 by the Obama administration, prohibited internet providers from charging more for certain content or from giving preferential treatment to certain websites.

After the commission voted to repeal the rules in December, opponents argued the repeal would open the door for service providers to censor content online or charge additional fees for better service, which could hurt small companies.

In a column published on CNET on Monday, Ajit Pai, the FCC's chairman, said the repeal was good for consumers because it restored the Federal Trade Commission's authority over internet service providers.

The repealed rules

Under original rules, broadband service was considered a utility under Title II of the Communications Act, giving the FCC broad power over internet providers. The rules prohibited these practices:

Blocking: Internet service providers could not discriminate against any lawful content by blocking websites or apps.

Throttling: Service providers could not slow the transmission of data because of the nature of the content, as long as it was legal.

Paid prioritization: Service providers could not create an internet fast lane for companies and consumers who paid premiums and a slow lane for those who didn't.

What's everyone worried about?

Many consumer advocates argued that once the rules were scrapped, broadband providers would begin selling the internet in bundles.

Another major concern is that consumers could suffer from pay-to-play deals. Without rules prohibiting paid prioritization, a fast lane could be occupied by big internet and media companies, as well as affluent households, while everyone else would be left on the slow lane.

Some small-business owners are worried, too, that industry giants could pay to get an edge and leave them on an unfair playing field.

"(Internet service providers) will have the right to discriminate and favor the internet traffic of those companies with whom they have pay-for-play arrangements and the right to consign all others to a slow and bumpy road," Jessica Rosenworcel, a Democratic member of the commission who voted against the appeal, said in an emailed statement Monday.

Some states have taken measures to ensure the rules stay in effect.

In March, Gov. Jay Inslee of Washington signed a law that effectively replaced the federal rules. Others used executive orders to force net neutrality.

Still, several state legislative measures have failed, some are still pending, and not every state has taken such actions.