In 2004, a group of technologists and activists created an organizational tool called TXTmob that allowed protesters at the 2004 political conventions to communicate through short text messages that were widely broadcast through SMS to the cell phones of a group of people.
Two years later, web-based podcasting startup Odeo was failing, and its board members decided to spend a day in small groups brainstorming other ideas to "reboot" their business. One group met on a playground; sitting on top of a slide, group member Jack Dorsey proposed an SMS broadcast system similar to and inspired by TXTmob (see Figure 3-1).
And thus Twitter was built in March 2006. The following year, at the South by Southwest Interactive conference, the service reached its first tipping point when usage spiked from 20,000 messages per day to 60,000 messages per day; thousands of conference-goers used Twitter to find one another and to comment on panel sessions in real time. As of May 2007, 111 microblogging systems were in operation, but Twitter is by far the most popular today.
Figure 3-2. Numbers and underscores in your username typically lead to fewer followers.