In the last couple of weeks there has been an apparent increase in spam entries on the diary and user pages. I'm under the impression that spammers are "testing" the community at the moment, checking how long a spam stays alive depending on it just being spam, containing some map related content, if the spammer claims to be female, if a location is given, etc.
Most of the spams appear to be handcrafted, so tools to keep out automated spams will not help much. So lets think about what the spammers hope to gain: The number of potential victims in the OSM community that might buy spamvertized products appears to small to make much profit for the spammers, so they are probably after something else. My guess is that spammers try to boost their page rank by creating links from this trusted community site to their pages, so they are placed better in search engine results.
I suggest to change the site software so that users can only create links to some whitelisted websites on their diary and user pages. All other urls in those pages would only be displayed as text, so any interested reader could still copy/paste them in his browser address bar to view the page, but there would not be a clickable link.