As i know, one from the longest running, signature campaigns is Bitmixer. Probably no one has such a good reputation as they have.
What does signature campaigns have anything to do with the type of service they provide? They can run a signature campaign for months and yet run a fraudulent service.Take betcoin.ag for example.Also Bitmixer is weeding out spammers from their signature campaign,make sure you aren't one of them. 