The emoticon turns 25 years old on September 19 and man recognised as having typed the first one - Carnegie Mellon computer science professor Scott Fahlman - intends to mark the occasion with a cookie.

In the meantime, Fahlman will brace for the inevitable parade of press inquiries, entreaties from emoticon enthusiasts and brickbats from emoticon critics. The anniversary has already inspired an emoticon contest at Yahoo.

I recently had a pleasant email chat with Fahlman in which he speaks of how his 'invention' has brought him fame, not a penny, and a meeting with his favourite author - Neal Stephenson - who in a 1993 essay eviscerated emoticonists, including Fahlman, only to retract that assessment a decade later. What follows is an edited transcript of my chat with the Father of the Smiley:

Hi Scott: ... Do you ever get tired of these interviews? :-)

Yes, but our university public relations people love them, and I'm happy enough to go along. It's a weird thing to be famous for, but it's nice to be famous for something.

Do you use emoticons? If so, when?

Yes, I use the two that I invented, :-) and :-( , in email messages, plus occasionally a couple of others such as the winky face, ;-). I don't like the noseless variants, :) and :(

I think they look like frogs, though I might prefer them if I did a lot of text messaging on a cell phone - one less character to type the hard way.

For some people, making up really complex smileys is a sort of hobby - you know, things like 'Uncle Sam, Santa Claus, and the Pope being eaten by a python' - but I've never been into that and never use these. If you have to explain what the thing is, it's not really helping with your communication - at least, not in the same way.

Are you going to celebrate the 25th anniversary in some fashion?

I think we'll have a little local party for the Carnegie Mellon computer science community. There's a local restaurant chain, Eat 'n Park, that (by pure coincidence) is famous for their round smiley-face cookies. For a few dollars extra, they are willing to make me up a special batch of these with the face drawn on sideways. :-) So we'll probably serve a bunch of those.

We thought briefly about having some sort of symposium to mark the occasion, inviting a lot of experts on online communication and semiotics and the history of writing systems. That would be fun, but I didn't want to spend the time to make this happen - I'm trying to focus on my own research in artificial intelligence. (Fahlman leads the DARPA-funded RADAR project.)