Used to be "net neutrality" meant internet service providers (your friendly local ISP) would treat all data packets the same. Your email, the website you are viewing, the music you are downloading, at bottom are just bits (ones and zeroes) traveling over the net. For convience the bits are grouped into "packets" of perhaps 2048 bits per packet or more. Each packet has an address that tells the various routers and computers and hardware of the net where to send the packet.
Right now all packets are treated equal. No packets have priority over other packets. When the net slows down, everyone's packets travel slowly. Misery is shared equally. that's net neutrality.
Some folks want to change that and allow priority schemes where high priority packets go first and low priority packets wait their turn. ISP's might offer priority service, pay more and your packets go first, your website loads faster. Taken to extremes it might mean the less well heeled websites might never load at all.
It also means that folks downloading movies and music can no longer tie up the net. Some ISP's have already been accused of packet sniffing, i.e. looking at the contents of packets, and putting the music and movie download packets on the slow boat to nowhere. This lets them maintain decent response time for websites and voice telephone calls (Skype) without putting in more fiber and more routers and more money.
What to do? On one hand I like the idea that my packets go as fast as anyone's and all websites load at the same speed. On the other hand I have nothing against putting download packets at the bottom of the heap, so my web service doesn't grind to a halt when some kid downloads the Beatle's White Album.
I don't like the idea of Uncle Sam regulating the internet in the interests of net neutrality. Some how I suspect that Uncle Sam's regulation would raise my costs, slow my service and make it harder for new players to enter the internet market. "I'm from the government and I'm here to help you."
In my humble opinion it would be adequate to rely upon the free market to sort this out. Some ISP's will compete by offering "pay-for-speed" services and some won't. Customers will be free to choose which ISP they subscribe to.
One other thing to watch out for. Some people's idea of net neutrality has nothing to do with packet priority and delivery speed. When these people say "net neutrality" they mean political neutrality. Political viewpoints of which they approve go thru and ones they disapprove of don't. These people are pushing for censorship under a disguised name.