Twitter has long battled outages due to overcapacity, but this morning was shut down for several hours by something much more sinister -- a denial-of-service attack. (Wired calls it "possibly the first [Twitter outage] ever due to sabotage.") Regular updates can be found on Twitter's status blog.

As the San Francisco-based messaging service explodes in popularity, it's become much more of a target for those spreading malware and phishing for personal information. In this case, it's likely been hit by somebody barraging its servers so incessantly with requests that legitimate users are shut out or the system shuts down entirely.

All this after internal documents were stolen and later published by TechCrunch.

Also this morning, Palo Alto-based Facebook has been experiencing outages of its own.

In the meantime, TechCrunch offers 15 alternative things to do in the case of a Twitter outage.