Image credit: Joanna Stern / ABC News

Twitter, the popular social networking site that lets users share updates in just 140 characters, has just announced that it has acquired Posterous, a micro-blogging service.

The terms of the acquisition are not being disclosed. Both companies announced the acquisition on their respective company blogs.

Posterous Spaces, the company's blogging platform, was an early competitor to Tumblr and  allows users to share text, video, and pictures with others. According to the post on Posterous' website, the product "will remain up and running without disruption. We will give users ample notice if we make any changes to the service."

A similar message is conveyed in Twitter's post, although it mentions there will be instructions on how to back up content in the coming weeks.

"Acquisitions have given us people and technology that have enabled us to more quickly build a better Twitter for you," it is also said.

Lots of hypotheses about what Twitter will do with the service are swirling around the tech industry, but there is general agreement that the message is that Twitter is looking to expand its feature set.

"It appears Twitter is looking to evolve from the status update service it started as to an information service optimized for sharing and consuming information and content," Gartner research director Michael Gartenberg said.