Internet Service Providers (ISPs) are attempting to change the law to allow prioritisation of internet traffic from, or to certain services, by creating so-called fast lanes. These fast lanes would not be created from new, faster infrastructure, but by slowing down your existing services. If they are to succeed, customers and business alike could start seeing additional fees added to use services that they can already use just fine now.
Net Neutrality is impending legislation that would prevent the slowdown of the internet by codifying the responsibility of ISPs to treat all data on their network as equal. This law basically says that "[Y]our ISP should give you the bits you ask for, as quickly as it can, and not deliberately slow down the data you're looking for." (Cory Doctorow, via the Guardian)
You very likely pay your Internet Service Provider (ISP) a monthly fee that gives you access to a certain amount of bandwidth (Mb/s) and a certain amount of data (GBs or TBs per month). These fees pay for the electricity to run the equipment, the purchasing of new equipment, and any other charges that your ISP may incur while serving you your data. Depending on where you live the plans can range from tens of dollars to hundreds of dollars, with varying speed.
With net neutrality, ISPs are required to give you your data as fast as possible. They are allowed to do network management (traffic shaping) to guarantee a certain level of service, but they are not allowed to specifically discriminate against traffic (say, YouTube or Netflix). This means that any sort of shaping must be done to all traffic.
Without net neutrality, ISPs would be allowed to charge additional fees on top of your current plans. They could offer a YouTube and Netflix addon, for people who want to be able to use their full bandwidth when using these services, or a lower latency addon for people who like to game or trade stocks. These addons would give you "better" access to services. But, this "better" access would actually be your normal pre-discrimination speed, not a faster post-discrimination speed! They want to charge you a second time for the exact thing you already pay for! Why should you have to pay double for internet just because you're watching Netflix? Does watching Netflix somehow cost more than watching YouTube or Vimeo?
The issue is ISPs are becoming overbearing. The ISPs job is to connect people, that is it. They should not be messing around with users traffic to suit their own corporate agenda. Companies should not be allowed to throttle their competition out of business. The internet is one of the only mediums in which people from all around the world can easily share their thoughts and ideas, cheaply, freely, and effectively.
Winning this would grant them the abilities to take out their competition, by slowing down customer access to the competing products or service, or by completely blocking them. The very idea of requiring a business to be under the control of another, at their whim, is frankly unsettling. We have antitrust and anti-competition laws in place specifically to prevent this sort of thing from happening.
As a society we already have low tolerance to censorship on the internet by government entities, yet we seem happy to entrust private corporations with the keys to the kingdom? Hoping that they won't use it to push their agendas? While providing them with no accountability? This could prove to be detrimental to the internet as we know it.
The internet should remain the way it was designed - free, an open place where people can freely converse, without governments and companies interfering.