Posterous, the online platform that specialises in ‘micro-blogging’ has been acquired by social media giant  Twitter. Originally a Y Combinator start up, Posterous has been growing rapidly since it was founded in 2008 with a growth of 50% in 2011 alone. Although this may not be the big reason behind Twitter’s latest buy. It also looks like Twitter are after Posterous’ 15 valuable employees, something I gathered from Twitter’s initial tweet about the acquisition.

 “Today we are welcoming a very talented group from Posterous to Twitter. This team has built an innovative product that makes sharing across the web and mobile devices simple—a goal we share. Posterous engineers, product managers and others will join our teams working on several key initiatives that will make Twitter even better.

Posterous Spaces will remain up and running without disruption. We’ll give users ample notice if we make any changes to the service. For users who would like to back up their content or move to another service, we’ll share clear instructions for doing so in the coming weeks.

We’re always looking for talented people who have the passion and personality to join Twitter. Acquisitions have given us people and technology that have enabled us to more quickly build a better Twitter for you.”

Posterous had the something along the same lines to say about it on their official website,

 “The opportunities in front of Twitter are exciting, and we couldn’t be happier about bringing our team’s expertise to a product that reaches hundreds of millions of users around the globe. Plus, the people at Twitter are genuinely nice folks who share our vision for making sharing simpler.”

However this is not the first time Twitter have snapped up a new start up for their staff, Whisper Systems, a security based company specialising in smartphone encryption was also picked up by Twitter late last year with the purpose of using their staff on Twitter’s own products and services.

Internet security firm Dasient was also acquired by Twitter earlier this year, with the intention of utilising their staff on Twitter’s own product, as Dasient stated on their blog.

 “By joining Twitter, Dasient will be able to apply its technology and team to the world’s largest real-time information network. As part of this merger, Dasient is winding down its business and is no longer able to accept new customers.”

With Twitter’s buying pattern being so orientated on staff and not so much on product it will be interesting to see what the social media giant has install for us in the upcoming year.

A list of Twitter’s other acquisitions is available here, who knows how many were purchased for the use of their staff.