Originally I had it set to only certain groups could have signatures like our team members and people who used points to pay, but since I'm about to update the bank anyway I made it so that all members can have a signature.
You should be able to create a signature if you go to the Edit Profile page at the top theres a tab for Signature. When you're writing a message there's a check box at the bottom that should say "Attach Signature" and that adds it to your message. Also on blog comments it doesn't seem to appear, probably because they're just comments but on actual blog posts you're able to, I just checked.

Oh and if you click on the Edit Settings link there's an option that says "Always attach my signature" which you can use as well!

@Leandra Thanks so much! I just feel it makes things look fuller and more happening here on ds

I love using that feature. I use it to advertise the different social medias for this site. :) 

@Leandra Thanks for enabling them!! I just wish that they were able to go on the comments too I've seen that before on other forums and stuff so maybe it's a possibility on here too