I think that user should have an option to allow/disable this feature. It can be abused for "stalking" people. I really don't want anybody to be notified that I just posted an answer or a question.
I don't have anything against RSS feeds for user activity, but there should be an option to disable it.
I don't want people, or my employer, or anybody around me to have the possibility to see what I'm doing right now.
EDITED: removed a note about content generators ...