Who: Jack Dorsey, 30
What: Twitter.com, a global community of users who stay connected through instant messaging, texting and online posting
Where: Based in San Francisco

It was only a matter of time before those pesky things called "conversations" became obsolete. Anyone with a cell phone or personal computer has experienced the subtle social shift taking place in the way people communicate. Commit to a three-minute phone conversation? No way; send a text instead. Wait for your friend to check his e-mail? Better not waste your time; an instant message is easier. In this technology-driven era, people are constantly looking for the fastest, easiest way to communicate, and anyone who's smart enough to recognize this movement would be wise to capitalize on it now.

Like all good entrepreneurs, Jack Dorsey had his finger on the pulse of pop culture when he started working on Twitter.com in March 2006. Unsatisfied with his job at a podcasting company, Dorsey began looking into the mobile phone industry, which he felt was becoming huge. "I've always been fascinated by IM--letting people know when I'm at lunch or at work," he says. "I wanted to set up a way to receive messages about what my friends were doing no matter where they were."

With help from some co-workers, Dorsey began working on Twitter.com as a side project, officially launching the site in August 2006. Twitter is a global community that keeps users in constant contact with one another through texting, IM or their personal Twitter pages. Anyone connected to you as a friend instantly receives your messages. This is no MySpace or FaceBook, though; don't expect to see a lot of pictures or blog entries. The site instead is a simple way to quickly let your friends know exactly what you're doing or thinking at any given moment. Typical messages range from mundane updates, such as "at work. working on: email," to random thoughts: "my emotional homework for the week: clean out my glove compartment, then go the arcade and spend $3-$5."

With no startup money invested, Dorsey has relied solely on word of mouth to get his site going. So Twitter was slow to get going for the first couple months. "Bloggers were the early adopters to push it, and from there it was a matter of them forcing their friends to join," says Dorsey.

Twitter caught its first big break when it helped sponsor the South by Southwest Conference in Austin, Texas in March 2007. The popular music and media conference has become a favored gathering among bloggers and other tech-lovers, making it a target audience for Twitter. Knowing that the majority of his users are bloggers, Dorsey set up two plasma screens displaying real-time twitters between conference attendees--and they were hooked. Since the conference, the number of users, updates and messages has doubled.

"The response to Twitter has been amazing," says Dorsey, who admits he's currently not receiving any income for his "side project." "We've had some interest from cell phone companies in helping us cover some of the expenses, but my main goal right now is purely on growth. For a company like this, that's doing something no one has ever done, growing is the most important thing."