"What Twitter really represents for some people is legacy," says Jeff Pulver, who co-founded Vonage and hosts Twitter conferences in cities including Los Angeles, New York and Tel Aviv. "Words, ideas, thoughts are small postcards that people can send to themselves in the future because now there's a digital trail as to who said what, when and where."

From that point of view, Twitter is a timeless platform containing a trail of expressions, leaving a path that may help people in the future discover how and why we got there.

What about that third question: Will Twitter survive for five years? That depends on whether Twitter's co-founders can turn this thought-catching-machine into an cash-creating engine. Twitter co-founder Biz Stone said in July that Twitter will make money this year and "will continue to add ways to make it more valuable." If Twitter proves to be profitable, it will likely stick around for years to come. If not, no matter how much folks enjoy using the service, it won't.

Part of why Twitter works is the charm of its140-character limitation. It forces users to communicate their thoughts succinctly and clearly, while doing it in written form. It doesn't always work, and when it doesn't, it can cause misunderstanding and confusion, or worse, no response. (Or even worse, it can be used for no good at all, such as celebrity death hoaxes.) The quality of Twitter relies on the quality of the connections happening on the site.

"It helps people more transparently connect with each other, and companies to more cleanly connect with the customers," says Dr. Pamela Rutledge, director of Boston-based Media Psychology Research Center. "If people aren't achieving a quality relationship with others online, they wouldn't use it, and it wouldn't work." Peggy White, publisher of Double X, a webzine spin-off from Slate that focuses on women's issues, says Twitter and social networking work because they're improving the quality of relationships and communication both online and off.

In short, Twitter gives people a chance to control their message in a short burst. Once the message is out there, it may take a path not intended by the originator. The beauty of the service is if you let go of controlling the message, you typically discover better or more useful information. It all depends on the users who send Tweets.

"People discover their voice matters," Pulver says. "When you have a platform that aggregates people making statements, and these statements move to the top in a democratic fashion, that moves markets."

Love it, hate it or disregard it, that's why Twitter matters.

Anthony Massucci is a senior writer and columnist for DailyFinance. You may follow him on Twitter at hianthony. He is speaking tonight about why Twitter matters at a New York City event hosted by Jeff Pulver.