tumblr, outages, service disruption, social networksTumblr is entering hour four of an outage that the company attributes to one of its uplink providers.

“Recovery is moving quickly and we will return to full service shortly,” the company said, repeating a statement first issued three hours ago.

Tumblr hosts more than 75 million blogs and sees about 25 million unique visitors per month.

Update: A high rate of packet (data) loss on the Internet Traffic Report combined with other reported outages, including Google’s App Engine, suggests the problem lies deeper in the guts of the Internet than Tumblr’s hosts.

Tumblr seems to have repaired its own domain but says it is still addressing problems with custom domain blogs.