Referer spam, AWStats, and nofollow
Seeing a ton of referer spam lately -- which shows how well these "SEO" twits do their jobs, as my logs aren't public.
Nonetheless, referer logs are a perfect place to add nofollow attributes to outbound links -- which would at least reduce the incentive to referer-spam sites.
I use AWStats -- there's already an RFE asking for this feature to be added. I offered a patch to do it -- you can grab it here in the meantime. The patch is against v6.3. Basically adds a NoFollowLinks config parameter, defaulting to 1 (on). If it's on, reported links get a rel="nofollow" attribute.