First of, you will notice I am using a signature. Therefore I am the first to acknowledge signatures are great for members to advertise their work or say something about themselves. Having said that, displaying signatures is one area that is easily abused on a discussion board and can quickly ruin the aesthetics of a site. If not controlled, signatures can turn the board into one big advertisement board. Surely you don't want that to happen. My suggestion is 1. put a cap on the size of the signature to be displayed and 2. limit the number characters to display in the signature (maximum 120 characters). Members who wish to show more in their signature can pay extra if they wish to go above the maximum limit. This way, the aesthetics of the site is maintained and extra money is raised to run the site.