What's the deal with Net Neutrality?

• What are the actual motivations for NN? Who are behind it? What do they gain with NN? What do general users gain with NN?
• Aside from Verizon and other telecom monopoly wannabes, who are against it? What reasons/objections do they propose? What can we lose if NN goes into effect?
• Can monopoly not be dealt with by existing anti-trust laws?
• Considering the frightening resemblance between the state of cable TV and Verizon's recent bullpomegranate, how worried should I be?
• What questions am I being too dumb to ask?

1) Cable/service companies like Verizon, Comcast, Time Warner, etc. If there is no net neutrality, they have the power to filter content they provide to you as they see fit. If you have Netflix, Comcast can limit the content you get from Netflix to almost unusable levels and proceed to charge you money to be able to use it while at the same time, push their own online video sharing "OnDemand" service for much cheaper without any impedance. With NN in play, they have no choice but to give you content of their competitor if you want it. Think of it like Windows 8 making pages load slower on anything but Bing because you're using Chrome or Firefox as a browser instead of Internet Explorer. That doesn't happen and Windows doesn't care in the slightest if you have Firefox and you incinerate any trace of Internet Explorer off your hard drive.
2) Any startup company will be against it, as well as free-content giants like Facebook and Google. For example, Google's main focus is getting content to the consumer in the easiest, cheapest way possible, not because they're philanthropic or acting out of good will but because their entire business model depends on it. Without NN, it can be seen as a barrier for accessing content people want to see and thus will result in less ad revenue.
3) Oligopolies exist in so many industries that it's naive to say that businesses are limited by any sort of government intervention. Think of the oil industry, the food industry, the healthcare industry, the cable service providers and tell me that one of them are controlled in any meaningful way by today's laws as to benefit the average consumer.
4) That picture is funny because it would be something a cable company could do but it's unlikely that it will happen in that kind of satirical way. In the same way that getting ESPN over inflates your TV bill, your internet service might hike a little bit due to everything being passed to the consumer (as it almost always does). The broader picture is that new breakouts like the next Facebook or the next instagram or the next big social media craze will probably not happen. That's just speculation though. How worried you should be depends on your priorities.
5) Research the origins of NN and the whole quarrel with Verizon. As I understand it, NN isn't even that definitive or meaningful and was brought up as a weak guideline that the current companies are reluctant to follow. The implications of what may happen can always be deduced by looking at who's supporting which side, whether it's by principle or business interest ie money, but the problem itself and how it came to be is something you should research on.

I'm not too well versed on this subject so take it as you will.