Net neutrality is the principle that all data on the internet is treated equally. This means that data cannot be favourable processed if someone pays more money (as an example consider a motorway toll bypass where people who pay enter reach their destination quicker).
The issue for consumers is that should net neutrality by overturned we may find ourselves having to pay extra for some of our content and big companies may be able to give priority to their own content at the expense of their rivals.
The US government is concerned that net neutrality may be stifling investment in infrastructure from some of the bigger companies as the neutrality means that they can’t monetise their investment.
In any event watch out on the 12th of July as big companies will carry out a day of action, slowing down content to simulate what might actually happen. If you start seeing messages about slow speeds, don’t worry it is just a demonstration so be patient and wait for tomorrow!