Ok some people have had problems with signatures, and I don't see why.
just go to your profile, click edit signature or click here
this should take you to the signature area. Then in the dialog box place any ordinary signature image using img tags
this will add a signature to your profile and on the site, mind you, you can upload signatures onto the server here, but max sizeis 400x90 or 9.8kb.
If you host it elsewhere, like imageshack, there is no real size limit, but please be mindful of other users and don't use large massive signatures, nothing taller than 120 in height. I have made a new user account and will post below with a signature.