The tipping level for Twitter's popularity was the 2007 South by Southwest Interactive (SXSWi) convention. It had 400,000 tweets posted for each quarter in 2007. This grew to a hundred million tweets posted per quarter in 2008. In February 2010, Twitter people had been sending 50 million tweets for every working day. Work on the venture started out on March 21, 2006, when Dorsey published the initially Twitter message at 12:50 p.m.