If you haven’t moved away from Posterous yet, you probably should. As pointed out on Hacker News, Posterous’ SSL certificated expired recently:

posterous ssl fail 520x426 Is Twitter about to kill Posterous? SSL certificate has expired, promised export function still MIA

If that’s not a sign that Twitter is looking to kill the service, I don’t know what is. Twitter acquired the shortform blogging company back in March. At the time, its users were told Posterous would remain operational, but we suggested to our readers that they look for alternatives anyway.

Here’s an excerpt of the Acquisition FAQ document:

What happens to my Space? Will Posterous eventually shut down?
You can use your Space(s) exactly as you have in the past. We’ll give you ample notice before any changes or disruptions to the service and we’ll provide specific instructions for exporting your content to another service.

How can I backup or export the content of my Space(s)?
We’ll share instructions on how you can backup the content of your Space soon.

Can I export my Space’s to WordPress, Tumblr, Blogger, or another service?
Over the coming weeks we’ll provide you with specific instructions for exporting your content to other services.

Note that this was posted published seven months ago. Since then, we haven’t heard anything from Posterous regarding the promised backup and export options: the official blog hasn’t posted anything and the Twitter account has only tweeted in regards to the site’s outages.

We have contacted Posterous about the SSL certificate as well as the lack of an update for an export function. We will update this article if and when we hear back.

In the meantime, LifeHacker has an excellent guide explaining how to back up and migrate your Posterous spaces to Tumblr, Blogger, or WordPress. If you’re looking to move to something else, however, you’re out of luck.

Update at 3:00PM EST: Posterous is looking into the expired SSL certificate.

Update at 4:30PM EST: Posterous is working properly again. Still no information about that export function.

See also: Twitter-owned blog service Posterous loses multiple databases, suffers 17-hour outage

Image credit: dcubillas