Over a million followers can’t be wrong: Ashton Kutcher is the man. (Sorry, CNN.) In its popularity and utility, Twitter is the hottest thing since e-mail. But is it really that new? Well, that’s up for discussion – but it’s cool to see a new way of applying what is effectively an old idea can make it new again.

Remember the mailing list? And Yahoo Groups? From a technical perspective, Twitter is not much different. Back in the day (yeah, I’m now old enough to use that – damn you, technology, for aging me so quickly!), you could join a mailing list or a newsgroup or some such similar tool, and after subscribing to it, you and everyone else on the list would receive messages sent to the group address.

Twitter is basically the same thing. You follow someone (like subscribing) and when they tweet, you get the message. Same concept – but with fewer characters and the bonus of SMS.

Is it a revolutionary new idea? Technically, no. But with the distinct advantage of mobility brought by SMS, the site’s rising popularity and media coverage, not to mention Ashton Kutcher et al… well, it’s a tough combination to beat. So what’s the next old idea to get a big tech shift? What will be the next tool to revolutionize the way we communicate, work, or play?

It’s just too bad I can’t answer all of that in 140 characters or less.