Today is the third anniversary of Sina Weibo. They launched their service on Aug-28 2009, but let's look back over their 3 years tracks :
May Sina CEO Charles Chao published the plan of their Weibo service on their event in Chengdu.
Aug-28 Sina Weibo started their service as a public beta.
Nov-2 The registered users of Sina Weibo exceeded 1,000,000 people.
Aug-28 Their first anniversary (The registered users exceeded 30,000,000 people ).
End of Oct Their registered users exceeded 50,000,000 people.
Nov-25 They started to deliver community feature called "Weiqun".
Mar-2 They announced that their registered users already exceeded 100,000,000.
Apr-7 They changed their domain to "weibo.com".
May-13 They started to deliver certified users ("V") service.
Jul-21 They released special Android smartphone with HTC.
Jul-27 The follower of "Yao Chen" exceeded 10,000,000 people.
Jul-28 They started to deliver their light-blog "Qing".
Oct-21 They intensified the search service on their Weibo as "s.weibo.com".
Nov-3 They started to deliver the Weibo number called "Wei Hao".
Mar-1 Instagram start to support Sina Weibo.
Mar-1 It started that the search result from Sina Weibo was displayed on Baidu.
Apr They started to deliver ads service on their platform to the public.
May-9 They started to deliver corporate page version 2.
May-16 They announced that their registered users become 324,000,000 people.
May-28 They published the new rules for users on their Weibo.
Jun-8 They formally started the revenue sharing model between game developers and Sina Weibo( the rate of 7 to 3).
The middle of Jun They formally published their LBS platform to the public.
Source => TechWeb