Blog comment spam -- advertising slipped into the "comments" section of blog entries -- has been around awhile. It tends to trickle in. Various schemes exist to combat it, but most blogs are completely unprotected.

Though the mainstream press hasn't noticed, there was a radical increase in spam over the weekend. Who's doing it? And why the sudden increase?

I asked blog-owning visitors to my personal blog, The Raw Feed, to comment on whether or not they experienced a sudden rise in comment spam, and all who posted comments said they had.

A blogger with a very popular tech blog said spam attempts jumped from 800-1200 per day to more than 4,000 on Sunday alone. Other sites are showing big jumps as well.

My guess is that some blog spammer out there has been innovating new ways to automate attempts to post blog spam, and has figured out how to be far more prolific than anyone has previously been able to do. And if one spammer has a new, highly effective technique, then dozens, then hundreds, of other bloggers soon will as well. If that's the case, it's bad news for bloggers and good news for the companies such as Microsoft and others who make software to protect against comment spam.

But it's just a guess.

I'm also guessing that blog comment spam is about to become a huge problem, forcing a new arms race between spammers and bloggers and making blog comments less appealing.