I see a lot of people looking to buy or sell signature space.
I've put together a place for people who are looking to do this sort of thing to get in touch with each other. There's a place to buy/sell links, signatures, or just swap. Or whatever.
Have a look:
www.sellmysignature.com. I know, there's no activity, but once people sign up and start using it I'm hoping it'll become a good resource for this sort of thing.
Buy/Sell Signature Space
Linear Mode
