Most of the blogs have a nofollow for user content by default these days. Multiple instances in a site of the same text and link don't bring much (I think) and are being threated as "simmulars" or just one. If you manage to manually ad a different "signature" each time, it would be probably better. Just a link in your profile would make the same effect, exept the traffic by other people clicking on your signature.
Thanks a ton for sharing these tips. I have been trying to implement all of these strategies into my routine and so far it's been paying off pretty well.