On Tuesday, the US Federal Communications Commission (FCC) announced that it planned to vote on an order to roll back Obama-era rules governing net neutrality.

Simply put, net neutrality means that all data on the internet is treated equally. An internet service provider can't prioritise certain companies or types of data, charge users more to access certain websites and apps, or charge businesses for preferential access.

Advocates of net neutrality argue that it ensures a level playing field for everyone on the internet. Telecoms firms, however, are largely against it because of the additional restrictions it places on them.

But with the Republican-majority FCC likely to vote on 14 December in favour of rolling back the order, what might the American internet look like without net neutrality? Just look at Portugal.

The country's wireless carrier Meo offers a package that's very different from those available in the US. Users pay for traditional “data” — and on top of that, they pay for additional packages based on the kind of data and apps they want to use.​

Really into messaging? Then pay €4.99 ($5.86 or £4.43) a month and get more data for apps like WhatsApp, Skype, and FaceTime. Prefer social networks like Facebook, Instagram, Snapchat, Messenger, and so on? That'll be another €4.99 a month.

Video apps like Netflix and YouTube are available as another add-on, while music (Spotify, SoundCloud, Google Play Music, etc.) is another, as is email and cloud (Gmail, Yahoo Mail, iCloud, etc.).

Net-neutrality advocates argue that this kind of model is dangerous because it risks creating a two-tier system that harms competition - people will just use the big-name apps included in the bundles they pay for, while upstart challengers will be left out in the cold.

For example: If you love watching videos, and Netflix is included in the video bundle but Hulu isn't, you're likely to try to save money by using only Netflix, making it harder for its competitors.

And without net neutrality, big-name apps could theoretically even pay telecoms firms for preferential access, offering them money - and smaller companies just couldn't compete with that. (It's not clear whether any of the companies named above have paid for preferential access.) An ISP could even refuse to grant access to an app at all unless they paid up.

Democratic Representative Ro Khanna of California originally shared the Meo example on Twitter in October.

“In Portugal, with no net neutrality, internet providers are starting to split the net into packages,” he wrote. “A huge advantage for entrenched companies, but it totally ices out startups trying to get in front of people which stifles innovation. This is what's at stake, and that's why we have to save net neutrality.”

Technically, Portugal is bound by the European Union's net-neutrality rules, but loopholes allow certain kinds of pricing schemes like the one outlined above.

Yonatan Zunger, a former Google employee, recently retweeted Khanna's tweet, adding: “This isn't even the worst part of ending net neutrality. The worst part happens when ISPs say 'we don't like this site's politics,' or 'this site competes with us,' and block or throttle it.”