Is Sina Weibo down?

Clicking on many people's Weibo pages shows an error message: "This user does not exist." Could it be that all users have been deleted? Sina seems to lack the capacity in building large networks.

Let's Google it:

AilinTao‎: What's going on? Sina Weibo seems to be down....

Twitter - seconds ago

PinkyJie‎: RT @grahamiao: Sina Weibo is down... The site can be opened, but accounts cannot log in.

Twitter - 1 minute ago

p3p3pp3‎: Is it down nationwide? RT @xxlydjh: Is it just in Shanghai? RT @gusisong: So slow, is there any big event happening today? RT @p3p3pp3: Holy cow, Sina Weibo is completely down right now.