There's usually some emotional reaction associated with such behavior. Characterizing it as a broad failure of self-control oversimplifies it.
There have been internet communities that I've been a part of that I have been emotionally bonded to. You get to know some people well and suddenly it's more a social experience than intellectual. That's a completely different story, and you'd need more than self-control to stop going there if it was becoming a time-suck.