Blogging platform Posterous has announced via its company blog that it will be shutting down as of April 30th. The company was acquired by Twitter just under a year ago.

If you’re worried about what to do with your spaces stuff, Techcrunch is reporting that Posterous co-founder Garry Tan has started a new site called Posthaven which he says ‘will never shut down’. The site can be found here, and runs $5 a month.

Posterous founder and former member of the Final Cut Pro team at Apple. Sachin Agarwal says that Posterous’ mission when it launched in 2008 was to “make it easier to share photos and connect with your social networks.”

As of April 30th, however, Agarwal says that its focus will be 100% on Twitter. So the site is shutting down completely as of April 30th. That means no more viewing or editing of content at all, period.

This means that if you still have any content still on Posterous, now is the time to get it off. Agarwal points to WordPress and Squarespace, both of which have importers for Posterous.

There is also a ‘backup’ option that you can request here, which delivers a zip archive of your spaces.

“We’d like to thank the millions of Posterous users who have supported us on our incredible journey,” Agarwal adds. “We hope to provide you with as easy a transition as possible, and look forward to seeing you on Twitter.”

Posterous’ acquisition came as somewhat of a surprise last year , especially as it was emphatic just 19 days before that it had ‘no plans to sell’. We mentioned at the time of sale that it was unlikely Posterous would remain up and running forever. It took about a year for it to finally give up the ghost for good. Despite saying that it would offer the backup feature within weeks, it took until December of last year before that was available.

Posterous was a pioneer of the ‘cross post for social networks, which allowed you to make one post on your Space and have it automatically appear on Facebook, Twitter and elsewhere. Since then this has become a somewhat standard feature, though it has been mitigated a bit as these individual networks guard their silos like mother hens.

Image Credit: Chris McGrath/Getty Images