I don't care for the spammers threads, but unfortunately that's part of society now-a-days. Spam and junk mail.
Old threads, sometimes I find them interesting so I don't mind if they are bumped up.
Links to other blogs, if the person just puts their blog link somewhere in their post, sort of like an after thought, I don't mind. But if they are actively trying to get others to go to their blog and using the forum as another way to "advertise" I don't care for that.