Twitter just announced a new feature for people using the service via SMS text messaging. Called Fast Follow, it has one big advantage — you don’t need a Twitter account to use it.

With Fast Follow, if people want to receive updates from a certain account, they can just text “Follow @username” to the number 40404, and Twitter will start sending the tweets to their phone. In a blog post outlining the new feature, Twitter encourages readers to “try it out the next time you see a Twitter @username at a restaurant or store, on a billboard or on TV, or if you hear one mentioned on the radio.”

In other words, this seems like a way for Twitter to encourage businesses to make their Twitter accounts a big part of their social identity without necessarily alienating people who haven’t joined the microblogging service yet. The question is whether Fast Follow will actually be fast enough and, more importantly, simple enough for the less tech-savvy crowd that it’s probably aimed at.

The announcement, and the other SMS tips included in the blog post, also show that text messaging remains important to Twitter, even after it released its own iPhone app following the acquisition of Tweetie. In fact, Twitter has been making acquisitions on the text messaging front too, having purchased Cloudhopper, which built a system for distributing tweets via SMS, in April.