The tipping place for Twitter's level of popularity was the 2007 South by Southwest Interactive (SXSWi) convention. It experienced 400,000 tweets posted per quarter in 2007. This grew to 100 million tweets posted for every quarter in 2008. In February 2010, Twitter consumers were sending fifty million tweets for every day. Work on the challenge began on March 21, 2006, when Dorsey published the initial Twitter concept at 12:50 p.m.