But how would it hurt to join a signature campaign while you're starting out?
It could hurt the community if the signature is promoting a scam or ponzi(common with many sig campaigns) and it will hurt the
users reputation by showing the rest of us they are willing to sell their reputation to the highest bidder and thus their comments lose credibility.
I see 3 users in this thread alone promoting a scam.
Sadly I think most wouldn't care much if they thought a potential scam was in their sig as long as the btc kept rolling into their wallet.