I didn't know you could track users without +friending them either, until recently. It's very useful for some high-end titled players, so that many people can track what they're doing. It's good for them, good for the site, and it would be a pain for them to have to +friend every person who wants to track them.
In the meantime I think I've +followed some people. I'll go check on Windows 7 though. :-)
The only way to block out users is from sending you private notes and messages, as well as the chat screen when you actually play.
Otherwise, forums are free game. There is some etiquette that is recommended, but the staff does not involve themselves in that area simply because you can cease using it (like reading and contributing to forums).
Chess.com is not Facebook, so no superblock feature here.