I’ve been having a real problem with the site being hit hard by spammers lately. Consequently, I have turned comments off on most of the articles on the site at this point.
Due to the implementation of SPAM Karma 2 and Akismet, none of the comment spam actually made it to the blog. I was pretty amazed at how thoroughly these two pieces of software have filtered the incoming comments.
However, the comments not making it to the blog doesn’t mean that the spammers haven’t done any real damage. Twice now I’ve come home to find my comments disabled by my provider, due to basically a Denial of Service attack being executed on the site by these morons.
I found a great page at the WordPress Codex on Combatting Comment Spam. I would encourage anyone currently dealing with this problem to check out this page. I will be implementing some of these ideas one by one over the coming weeks to see how much they help.
I’ll let you know of the success I have. In the meantime, if you aren’t running Spam Karma, I would encourage you to go take a look at it and its corresponding Akismet plugin. The combination of both has been highly effective in this corner of the web.
Bieber Labs 
Check your 404 page not found error list to see how many pages are “not being found” on your site. Many of these pages are not legit, but spammer bots trying to “find” pages on your site. This can hammer your server without you seeing the evidence through Spam Karma or Akismet. Consider trying Bad Behavior in combination with these to block these before they get in.
This is an issue the pros are looking at, but so far, Bad Behavior is the only one that blocks some of these evil doers.