Signature campaigns can be really profitable and I think most people on the forums are doing this in fact.
The signature campaigns are time taking for sure but it will give you back bitcoins for free and this is pretty nice, and its also pretty fast if you compare it with other free methods right ?
Some signature campaigns are worthwhile, but not all. Also, this will depend on the user's rank. The higher the rank, the better the chances of getting into a good campaign, and probably the greater the payout. It is also necessary to be attentive to the quality of the posts, because some campaigns take this very seriously.