@anxiouscatThere is no money to be made in making a low-load forum into a luxury. However, the same cannot be said for Netflix, Twitch, Youtube, any P2P or file sharing sites, or any sites that do not conform to whatever standards the ISP dictates.
Repealing net neutrality means that certain parts of the internet will very likely become a luxury, and those who use high bandwidth (gamers, streamers, small businesses like the one I work in that have to transfer large files) will have to pay premium rates or get throttled. The fear is where that line will be drawn.
Take a look at cable (or satellite) TV providers, many of which also provide internet. For cheapo package A, you get your local channels, maybe the huge networks. For medium cost package B, you get 140 channels, and for high cost C, you get all 600 channels. Plus, you can pay an extra $30 per month for HBO and Cinemax. The question is where do the sites you visit fall into thimgs? Are they included in A, or will you have to pay C? Will imgur and 4chan be part of the HBO package? How much do I have to pay in order to stream my favorite games on Twitch?