Dec 6, 2010 16:52 GMT  ·  By

Tumblr, the popular blogging platform, has been down for close to 16 hours now, leaving users to scramble to Twitter and Facebook to air their frustrations. The site greets visitors with an error message and a promise to return "shortly." Of course, 16 hours later, "shortly" is starting to get a whole new meaning.

"We're working quickly to recover from an issue in one of our database clusters. We're incredibly sorry for the inconvenience," the error message reads.

"This has been a slow and painful recovery, but we're almost through. We'll have more info to share as soon as we can post to our blog again," Tumblr adds on its Twitter account. This was three hours ago and, at the time of writing, the site still isn't up.

Many users, especially in the US, went to sleep last night with Tumblr down and are waking up to see that the service still isn't available. Many of its more rabid users are not happy and Twitter is filled with angry tweets.

"Some scheduled maintenance yesterday that wasn’t intended to interrupt service went haywire and wound up taking down a critical database cluster. Rebuilding the entire cluster has been a painfully slow and manual process, but we’re almost through. We’ll be posting a recap when we’re back up," Tumblr founder David Karp explained.

Outages are not unheard of in the tech world. Even the mighty WordPress.com has seen its fair share, one of the worst being early this year.

Twitter, of course, is notorious for its unreliability and the site struggled during the World Cup earlier this year. The microblogging site does a far better job at staying available these days, but downtimes are not uncommon.

Still, a 16 hour outage for a rather popular blog host, with millions of users, does not bode well. And, despite insurances, it looks like the team is still not done with the recovery process.