You don't sign posts.. You sign letters, or messages sent from you directly to another person which only that person reads and nobody else. What you are doing is like saying your name after you talk to a group friends. Yeah, that's right, it looks that STUPID.
When you sign things like posts, it makes you look like an idiot. If you look like an idiot, nobody will want you to do signature logos for them.
Take this advice now, or DIE.