And your first “twit” is something along the lines of “No idea why I’m here.”

That’s a good thing - neither does anyone else, and that’s what makes it something entirely new, and that’s why some people are very excited by it. I’m not sure whether this is just another passing fad, but it certainly has exploded over the last few months as its visibility has gone viral.

When people ask what the point is, I generally point out that until about 6 months ago, Twitter would send updates via SMS straight to your phone, no matter where in the world you were - hence the 140 character limit.

This meant it was an excellent way to send mass updates amongst a group of friends, such as the inanities that made it famous - “At Whatever Bar having a beer”, “sitting at starbucks on main st having a coffee”, and such like. It would effectively be a “ping”, letting people who have explicitly subscribed to your feed know where you were and what you were doing, so if they were nearby you could meet up.

As it got more popular, Twitter turned off SMS updates outside the US, UK, Canada and India, where presumably they have a deal with mobile providers. This took some of the steam out of it internationally, I think, but the increasing presence of internet-enabled phones means that we get around that limitation.

But that’s not the point - Twitter’s gone way beyond that now, as companies and celebrities pile in, some cynically using it as yet another marketing tool, some genuinely getting involved in a way that they never quite did with blogs.

Many draw comparisons between Facebook and Twitter, especially with Facebook’s most recent tweak to their design to make it more focused on twitter-like status updates (albeit without the character limit), but there’s a key difference - in Facebook, a relationship is mutual; both sides of the “friend” link see each other.

Twitter, on the other hand, is a network of one-way relationships - you choose who to follow, but they have no compulsion to “follow” you too. It’s this key difference from Facebook that makes it a more dynamic network, and lends it the more apt “microblogging” title. But then it’s not quite blogging, because it’s got a dynamism with replies and direct device updates with its short form that takes it closer to “real-time”.

Twitter is, if anything, closer to YouTube than Facebook - no-one quite knew what to do with YouTube at first, but people poked around simply because it was there; now YouTube and similar sites make up a significant chunk of internet usage globally. Twitter might not have the same bandwidth impact, but by bringing the web-2.0-read-write-web that one step closer to real-time, it represents yet another shift in how the internet is used to communicate.

Sign up - the web is changing apace.