Actually I can't even sell traditional 'banner ads' to Etronixs (due to an ad agency thing)... so they host the contests. Sponsoring prizes is no different than any other form of advertising, but this way a number of people can get something for free each month.

Posting your site as a signature is fine, but I totally object to messages that do nothing but advertise unless a user specifically requested such information in the same thread (for any other businesses reading, please don't attempt to start such threads yourself -- I can tell). Technically this thread counts as a "pure advertisement", but since people have been waiting so long for information I allowed it.