The big internet companies are at war over this simple service that allows people from all over the world to have text-based conversations with each other in real time.

"In terms of Windows XP, in terms of AOL, on their television and other internet properties, and Yahoo putting it everywhere, it shows you how much importance they give it," Avner Ronen at IM software company, Odigo, told the BBC's Click Online programme.

Clean, uncluttered interface

Other players are also looking to put instant messaging on their phones, and cable providers are also looking to put instant messaging on their networks.

"I think the understanding in the market is that this form of communication is very important in terms of increasing brand loyalty, and providing a crucial service for the end user," says Mr Ronen.

A filtering system allows like-minded people from around the globe to find one another. Odigo, with its animated faces, is a relatively advanced IM service.

But for the most part even the most popular services have remained basic and, most surprisingly, commercially free - or close to it.

The average instant messaging interface is still clean and uncluttered.

Be my buddy

But corporations want to be on your buddy list, coming up with names like Smarter Child. Add that name to your buddy list and you can chat all day long to your new resourceful virtual friend.

"What's cool about this is that all you have to do is add one of our screen names to your friends list and you can instantly start talking to it," says Jim Pawlika, director of production at Active Buddy.

Simply add the name Googly Minotaur to your buddy list and you can ask Radiohead details about their album and tour or take part in a competition.

This might be useful perhaps but it raises several questions, such as whether users should be cautious about giving up personal information during an informal spontaneous exchange.

Active Buddy, which produces the software that makes all of this happen, says the system is harmless.

"We've set something up that is 100% opt-in by the user. If you don't want to add the name to your buddy list, if you don't want to interact with the computer - don't. It's that simple," says Active Buddy CEO Peter Levitan.

"We simply put this option in front of you. If you'd rather use the fastest way to get this information, then great. But if you don't want to, if you just want to plod along - then be my guest."

Corporate appeal

There is no shortage of corporate interest in instant messaging.

With instant messaging gaining in popularity, companies would like to find a way to initiate casual conversations about their products and services within the IM chat boxes. But for some, this is going too far.

"I hate the idea," says William Sanchez, who keeps in touch with his Californian colleagues 2000 miles away from his New York office via Yahoo Messenger.

"I would never want a company to send me an instant message advertisement and as soon as that started I would instantly log off and never use the service again," he says.

"I liken it very much to unsolicited phone calls which many people hate - I know I do - and I'd stop using the service immediately."

But two things seem inevitable. Instant messaging looks like become the leading method for real-time communications with friends and business associates around the world.

And with its growth, companies will find ways, subtle or otherwise, of getting their share of what is currently the most valuable yet untapped real estate on a computer screen.