User blog comment:Sannse/Blocking Best Practices/@comment-1709282-20121010014844/@comment-8-20121010163851

I sorta consider spam to be part of vandalism :)

Most spammers don't keep coming back under the same username though, so a short block works well. Of course, one reason they don't, if that cross-wiki spammers are seen and blocked by the VSTF a lot of the time. They help protect all wikis with their blocks :)