+ Points.
Might brighten the place up a bit.
Extra personalisation of posts
- Points.
Pages taking longer to load.
A lot of repetition.
Possible increase in spam.
Some folks put ads to their own sites/projects in their sigs already (which I don't have a problem with BTW) but imagine what it would be like with banners
Besides, we already have avatars, profile pics, picture albums on our profiles, and threads on the forum where we can post any pictures we want to share.
Are we really so much in need of one more place to share a picture?
I'm not dead set against the idea myself, but i'd need some convincing.