martinibuster - 7:11 am on Mar 29, 2010 (gmt 0)
I would try to find a way that wouldn't allow anyone to post a URL
The intent of your idea is good and has merit but the application would prove impractical. Discussion and membership satisfaction would dampen if members could not link out to a news source, to an authoritative source of information, to photos, and to citations from other websites.
There are workarounds that minimize the spam problem such as stopwords, active moderation, a system for banning problem IPs, a bot-stopping challenge and removal of profile links. With all that in place the spam problem gets whittled down pretty fast.