Over the years I reckon I’ve tried hundreds of social networking sites, blogging and micro-blogging tools, online participatory spaces, and content sharing services. In most instances I register, set up a profile, have a look around, and abandon all in the space of about a week.

So how do I gauge whether I’m going to stick with a service or tool for longer? Well, more than a few times I’ve jokingly said that I know a social media service is useful as soon as I get a free coffee or beer out of it. And, actually, that’s about right. If I start using a site or service and can quickly find my friends and contacts there I tend to stick around because it’s my network, not the tool or service itself, which is useful and valuable to me.

Recently, Twitter has been the service that’s got me more free drinks than all the others combined.

For those not familiar with Twitter – and it’s getting difficult not to take notice with all the recent coverage in The Independent, Guardian and BBC – it’s a “micro-blogging” service where users can post tweets, 140 character messages in response to the question “what are you doing now?”, from their browser or one of the growing number of computer and mobile phone applications. But that’s not the key to it’s usefulness – it’s the ability to follow other users tweets which essentially makes twitter more a social networking tool than a publishing platform.

I was originally quite skeptical of Twitter. Why, afterall, would I be interested in knowing what others – some of whom I’ve met, others I haven’t – are doing at any particular moment in time. But then, as I started to follow more people, and more people began to follow me, I started to realise how very useful Twitter can be.

I’m up to just over 800 followers now, and follow around 500 people. These include social media experts, widely respected bloggers, journalists, lots of former BBC colleagues, Tower Bridge in London and even a Bishop,

So now, when I arrive in a town an hour and a half early for a meeting, as I did in Oxford two weeks ago, I simply Tweet: “arrived in Oxford early. now what?” and, within minutes, I’ve got a handful of suggestions of places to eat, one of which, I was told, had wifi. And when I started looking into staying overnight next week in Brecon Beacons National Park, a friend in Cardiff picked it up and retweeted it, the result being no fewer than a list of at least a dozen great hotels, personally recommended by people with firsthand knowledge of the area. There’s now even a service that allows twitter users to ask a question, and get help.

Whenever there is a big story or event, I can now follow the global discussion on Twitter – I did it for Eurovision and for the Obama inauguration. I’ve also used it to find and track breaking news stories such as the Jaipur bombs and, more recently, the Hudson River plane crash. In fact, if I’m not watching the 10 o’clock news, in most instances I hear about big stories on Twitter first because someone I’m following, somewhere, will tweet about it.

Not surprisingly, many journalists are also using Twitter to find contacts and content for stories – and a start-up has, even in these most challenging of economic times, managed to wrangle US $2 million in funding to create a service that sits on top of twitter.

Twitter has become, for me at least, more than just a social networking tool that’s fun to use – it’s the place where I initially hear about important news, where I get links to useful presentations and reports, and where I find most of the work related web based content I now consume. I’ve even pretty much abandoned my RSS reader because I get much better results from the human filtering that my twitter network does.

It’s useful, it’s fun and it’s free. And it’s about to get a big spike of new users in the UK if the speculation that @StephenFry and @wossy (Jonathan Ross) are set to enthuse about it tonight in front of a BBC1 audience likely to number 4+ million, and 70,000 twitter followers between then, turns out to be true.

According to hitwise, the number of twitter users in the UK has increased by over 1000% over the last 12 months and users of the services, by tweeting links, now send significant amounts of traffic to other websites – 10% of this, says the report, goes to BBC News.

If you’re at all interested in social media, you need to be on twitter and, if you’re a business owner, journalist, editor or marketing manager, you need to start thinking about your corporate twitter strategy as a way of engaging with your audience or customers.