FORTUNE — Email spam is at this point almost a non-problem, and Facebook has made great strides in curbing spammers (though they’re far from gone), but Twitter is rife with skeevy offers from pornographers and other hucksters. The problem appears to be getting worse, rather than better.
The company is doing what it can, but because its platform is so open, it’s a challenge. In a federal lawsuit filed on Thursday, it’s going after not spammers themselves but several companies that enable spam in various ways, such as allowing autoposting based on keywords. For example, if you type “SEO,” into a tweet, you might get hammered by a bunch of messages selling SEO services.
The openness of Twitter’s platform enables useful services like TweetDeck (which is now owned by Twitter), that, for example, allow users to merge their social-media activities. But also leaves the platform vulnerable to abuse. By going after outfits that violate the company’s terms of service, Twitter hopes to discourage other spam-enablers. “Taking legal action sends a clear message to all would-be spammers that there are serious and costly consequences to violating our Rules with their annoying and potentially malicious activity,” the company said in a statement.
Three companies and two individuals are named in the lawsuit. In its article on the lawsuit published Friday morning, The Next Web linked to the Web sites of all five defendants. All but one of the sites appear to have been taken down since then.
The Next Web’s Jon Russell notes that this will hardly make a dent in the problem. “While this lawsuit is unlikely to extinguish this type of automated software from existing and being used altogether,” he writes, “Twitter is setting a precedent and showing it will shut services like these down as and when it becomes aware of them.
