Twitter has been busy lately. Earlier this month, it announced its first acquisition, Atebits, and explained how its Promoted Tweets revenue stream would work. Now, the company has made another acquisition, a start-up called Cloudhopper.

Confusingly, Cloudhopper has nothing to do with cloud computing but is an SMS infrastructure company that allows Twitter to connect direct to mobile operator networks. The deal will mean that Twiiter will be able to push tweets to billions of mobile users worldwide.

News of the purchase was announced on the Twitter blog, although the details of the costs were not specified. "Twitter was inspired by SMS and we continue to embrace this simple but ubiquitous technology. In fact, Twitter's 140 character limit was designed specifically to allow for any tweet to be read in its entirety whether you're using a rudimentary mobile phone, or a more sophisticated Internet enabled device," wrote Kevin Thau, director of mobile products at Twitter.