It was inevitable. As Twitter has grown and started pushing into the mainstream, spammers have started ramping up abuse. At first glance, Twitter isn’t the most obvious target – you actually have to follow someone to get content from them, users don’t generally search it for high-cpc stuff like meds and lawyers, and how much spam can you really get into 140 character messages?

But I’m seeing more invites from users like the one below:

First: What is Twitterspam? How do I know this is a spammer?

When it comes to spam, most people “know it when they see it,” but it’s helpful to look at the specific signals that this user might not be worth talking to. First off, they have 180 followers and yet haven’t posted a single update. The photo is a dead giveaway. The bio is actually pretty well-done, it’s in English and it’s not outlandish, but the homepage link (http://my-pictures.no.tp/tlow/) – she’s in Portuguese Timor?

Second: Why spam Twitter?

Spammers have two reasons to abuse Twitter: monetary payoff, and because it works.

How can they make money by tweeting a bunch of random people? Well in this case they aren’t, at least not yet. The payoff has to be through the homepage link, which I’m not following and you shouldn’t either. You get a friend invite on a system that, so far, has been a medium of immediate, short, personal communication. Your trust barriers thus weakened, you at least want to see who it is. They don’t have any updates yet, so you click the homepage link and… Virus. Or a maze of PPC affiliate pages and redirections.

Above I said spammers are hitting Twitter because it’s working. How do I know? Look at the number of followers, and the ratio of people followed to followers. About 22 percent of the people spammed so far have responded. I don’t know how many click through to the home page link, but if half the people bother to go that far they’ve got an amazing success rate for spam.

I wish Twitter luck. I know a few people over there, they’ve got their work cut out for them. This sort of thing isn’t easy to fight, it’s an ongoing process. They’ve already taken some visible steps, like using rel=”nofollow” on the Bio link, which at least keeps away blackhat SEOs looking for sources of pagerank. They’ll probably have to do more, most of it on the backend where you and I will never be the wiser. Happy spamfighting!