Like various others here against the signatures I'm also one who loathes them. If I ever would add a signature to my post, the only thing I would add to it would be something along the lines that people who take signatures serious should be shot on sight.
KYM is about the only forum I’ve been on that doesn’t have this feature. This would also be restricted to forums, because from what I’ve heard the comment system as it is pushes the site’s capabilities.
Signatures are a common addition to forums that are just that: Forums. Or at least sites that focus on the forums a lot.
Here on KYM on the other hand, forums are the least visited portion of the site. Users on forum-orientated sites can benefit from the signatures as their forum posts are what defines them. For KYM on the other hand most people get to know each other through comment sections, media uploads, and profile walls. Our forum community is a closer bunch, but comments are still larger in quantity and wall comments are still the best way to contact someone.
Profile walls offer more customization and information than most forum-orientated sites, so it's not like you can't turn that into an extended signature (as many have done). Comment sections, image comments, and wall comments, all run on comments which won't feature signatures as those are something for forum posts.
Basically only a bare minimal portion of users would actually get good use out of signatures. It's hardly worth adding if you look at it that way. If we had an insanely big forum or were a site which basically ran on a forum, I'd find it something worth discusing, but KYM is no such site.
Plus, it gives visitors an incentive to create an account (and thus possibly contribute) if they want to get rid of signatures.
Signatures are only present on the forum, the area which, as I said before, is the least visited area of the site. I highly doubt people would make an account to get rid of signatures.
Alongside that idea brings a big issue with how the site is coded. James explained it a while ago but basically these profile options that decide how the site is viewed based on your account settings (such as making NSFW spoilers related to profile settings) require the site to have a different cache for each and every user. We don't have that space. Now I don't know if that applies here as well, but it's something to take in mind.