Ian Delaney examines the Twitter phenomenon: the next generation of social media communications or the scourge of a society that can't stop talking about itself?

New web technologies have a tendency to polarise opinions. Debates regarding the value and even the morality of social networks, blogs and wikis have exercised key thinkers since the birth of what tends to be called (albeit relunctantly) Web 2.0 since its dawn in 2004.

Over recent weeks, it is nascent web service Twitter that has split opinions the most. What is it? It's a way to send short (up to 140 characters) messages to friends and to read theirs. You can send and access these messages on the website, through SMS messaging or using an instant messaging client such as MSN Messenger. You can make these messages private - only visible to your friends on the system - or public.

You might wonder why something quite so inoffensive would cause any debate whatsoever. The site asks the question 'What are you doing now?' and users supply the answer. Unsurprisingly, the answer is pretty mundane for most people most of the time:

A: Waiting for the bus.

B: Deciding between marmite and marmalade for my toast.

C: Getting ready for a big meeting.

B: Have gone for two slices - one for marmite and one for marmalade.

A common reaction is thus, Are you mad? Why would anybody subscribe to a list of messages like that? The Guardian's Jack Schofield wrote on Sunday that he'd been "resolutely ignoring Robert Scoble's frequent mentions of Twitter in the hope that it might go away."

Twitter evangelists, and they are many, reply in various ways.

The extent to which Twitter yields noise over signal entirely depends on the number of friends you add to your network. While the initial reaction to the system might be to immediately add dozens of semi-strangers to your network in a MySpace-style popularity contest, the results of doing that aren't likely to be especially rewarding. Bobby Johnson of the Guardian says in reply to his colleague that: "Point is, you *choose* who you listen to. Choose well, and you'll be fine, it could be even be enlightening. Choose badly, and it's like a bunch of monkeys jabbering away."

People who post updates up to a dozen times a day (and more) would probably need to be blood relations or on their way to deliver vital medication to you in order to warrant a subscription delivering updates on their every movement. There's a certain analogy with blog posts here. Blogs that are updated several times a day aren't always as valuable as those updated weekly, with intelligent, witty, well-written content.

Socialtext's Ross Mayfield describes Twitter's virtue as allowing continuous partial presence. The ease and accessibility of posting, together with the informality of the medium encourages frequency of use.

The presence idea seems spot-on, and is developed further in a blog post by Elizabeth Lane Lawley. She suggests that Twitter provides a convenient way to tap into the working day of the people we care about, wherever they are and whatever they are doing:

This isn't about conveying complex theory - it's about letting the people in your distributed network of family and friends have some sense of where you are and what you're doing. And we crave this, I think. When I travel, the first thing I ask the kids on the phone when I call home is "what are you doing?" Not because I really care that much about the show on TV, or the homework they're working on, but because I care about the rhythms and activities of their days

If the Twitter messages you receive are boring and lack value, then you've probably made more friends than you should have, and with the wrong people. Pick the people who you might phone to ask 'what are you doing now?' would be the extension of this argument.

Twitter is also becoming a way to deliver services. BBC Headlines, Tube Services, events and software companies all exist as channels on the service providing a way to deliver news updates in an extremely flexible, inexpensive way to multiple channels and potentially wide audiences. As email seems to become increasingly unreliable and interruptive, a Twitter channel delivers the message at the audience's convenience and without spam.

It's incorrect to see these postings as especially ephemeral, though, I think. To a greater extent than an instant message, which disappears once the session is closed, Twitter messages are archived and now are even searchable using Google services, though hopefully, they won't be appearing in web search results very soon.

Social network blogger and consultant Pete Cashmore ought to be allowed the final word on Twitter, and its place in the evolution of social media, though: