Ross Mayfield offers an insightful analysis of Twitter’s growth. [Twitter is the service that lets you send short text messages between you and your friends, via the web or mobile phone. It powers my "last spotted" message on the top right of this page. Do sign up and say hello].

Ross says Twitter has “tipped the tuna” - which is to say it has started peaking, or has crossed the chasm, or indeed hit the tipping point. Ranged against those latter two cliches for breakthrough, I suspect the tuna one doesn’t have much of a chance, but still… it was a good post.

Offering up reasons for Twitter’s growing adoption, Ross writes:

“A couple of weeks ago it became a convention to start messages with @username as a way of saying something to someone visible to everyone. Within the limited affordances of the tool, people started to use it not only for presence, but a kind of shouting at the party conversation. Further, when you see an to someone who isn’t in your social network, you find yourself inclined to go see who it is or add them if they are a friend who just joined. This kind of social discovery goes beyond seeing friend lists on profiles, aids network structure and quickens adoption.”

I’m not sure the @username thing is much that’s new - we’ve seen that for years on the Guardian Gamesblog, and I suspect it’s been common elsewhere for even longer - but I think he’s spot on about the explorability and ease of use of Twitter. It’s fun to wander around, adding someone to your list is easy and offers quick reward (you start getting updates on what they’re saying) when you do.

The recipe for success here seems so simple it’s almost patronising to repeat it - the service is “cheap” in terms of effort required from the user, grows in value the more people use it (and especially the more people you know that use it, thus giving you an incentive either to get others to sign up, or sign up yourself), and offers instant gratification pretty much every time you log in.

But when you compare and contrast the effort required on some other social networking sites just to get signed up, or extract some meaningful output, you see just how hard it is to design that kind of simplicity in.

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