LOUISVILLE, Ky.—In any given second, an average of 600 Twitter messages ("tweets") are sent. The secret to its success: it's fun, simple and social—a set of criteria that all entrepreneurs should keep in mind when pursuing their ideas, Dom Sagolla said here Friday at Idea Festival.

Twitter's 140-character constraint has been crucial to the service's success, with Sagolla likening tweets to a poetic form or the punch line of a joke. "The power of Twitter is its simplicity," he said.

Sagolla should know—he was one of the original software developers involved in Twitter's creation, working alongside Twitter, Inc., founders Jack Dorsey, Evan Williams and Biz Stone. In 2006 they were developing Twitter as a messaging service to be used internally at their podcasting company, Odeo, Inc., in San Francisco. Twitter was originally designed for use on cell phones (not necessarily smart phones, which were in short supply a few years ago), which helps explain its character limitation. SMS messages can support 160 characters. A message exceeding this is broken up into multiple messages. Twitter's 140 characters fit comfortably within that limit.

Dorsey, Williams and Stone spun Twitter out in April 2007 as its own Web site and service. Sagolla, the ninth user to sign up for Twitter, lost his job soon after the service went live, when the company was trimming overhead—laying off half of its employees—in preparation for austere days to come. Still, Sagolla became an avid user of the service and spreading the word to whomever would listen. "I don't take responsibility for the idea; it was Jack's idea long before he joined Odeo," Sagolla said, adding, "I take credit for the addiction."

Sagolla later became involved in developing an iPhone app for President Obama's presidential campaign—Obama '08. The free app, which could also be used by iPod Touch owners, had a "Call Your Friends" component that organized contacts in an iPhone by battleground states (Florida, Ohio, etcetera). As part of the app, users could create reminder notes to themselves, indicating which friends they had called, who their friends planned to vote for and which friends wanted a reminder-to-vote call on Election Day. The app tallied (anonymously) the number of calls made to different contacts (noting the call recipient's location).

The Boston native now spends much of his time developing apps for iPhones and iPads and organizing events, via Twitter, where fellow developers can exchange ideas. When people ask Sagolla what's coming next in the world of Web and mobile apps, he said he always points out niche technology and niche social networks. This includes technology from Square, Inc., that enables artists and other merchants to accept credit card purchases via an iPhone, iPad or Android phone. He also pointed to Google's social networking site Orkut as an endeavor with a lot of potential.

Sagolla also advocates for Web sites and software that he believes should have a strong social impact, in particular Notforsalecampaign.org, a site created to support activists working to end slavery and human trafficking worldwide.

How often does Sagolla use Twitter these days? "I don't tweet that often," he said. "I try to get into it once or twice a day."

Image of Sagolla signing his book 140 Characters: A Style Guide for the Short Form, at Idea Festival courtesy of Larry Greenemeier