OneAndOneIs2

I see SimCity, the original "Build your own city" game, has been released under the GPL. It joins other noted games such as Doom, Quake, and Second Life in the category of commercial games that have been open-sourced.

A lot of people don't realize just how good an idea this is.

Take Doom - one of my all-time favourite games. Released in 1993, as shareware. I first played it when it came free with my first ever Linux installation. You had to buy the game to get all the levels, but the demo was superb. It sold a million copies.

Doom II came out a year or so later, and sold two million -id software's highest-selling game, apparently. Certainly the technical superiority of the game over anything seen before it (stop sniggering, it was cutting-edge in its day) helped, but the fact that Doom was spread over the Internet, legally and for free, played a huge role in making its sequel so successful.

Of course, that was a long time ago and by today's standards, Doom is primitive. So id was kind enough to throw open the source code, under the GPL, in 1999.

Since then, Doom has been ported to practically everything capable of running it. Even my little GP32 handheld can play Doom. So can the PSP. So can an iPod... By releasing the code, id has seen to it that Doom is still under active development even today, and running on a staggering number of machines.

Big deal, you might think. They don't make any money out of it.

True enough. But here's a thought for you: Everybody knows coca-cola. They know what it tastes like, they know if they like it or not.

So why do the coca-cola company bother to spend $2.5 billion advertising a product that everybody knows about?

Because they need to make sure that new, young consumers learn about how good coca-cola is, and remind the older ones how much they like drinking it.

The relevance? Although the original Doom game is so old as to be almost unmarketable, except for the occasional nostalgia kick, by open-sourcing it, id insured that when they brought out the next version, Doom 3, they didn't have to remind the old gamers nor educate the new ones how good a game Doom is.

They already knew, because although they might have mega gaming rigs with gigs of RAM, multiple CPU cores, and graphics cards with enough power to run a small city.. they probably still have Doom installed on their phone, their PDA, or their handheld console.

Doom is on virtually everything. It's even coming to the iPhone. Everybody knows about it, most people have it, any gamer will have played it.

Think about how much it would have cost id to port Doom to that many architectures. Think about how much it would have cost them in marketing to get the same level of exposure they got for free by giving away the source code.

Think about how much hype there was when Doom 3 came out.

And you'll know why it can be worth a company's while, releasing source code to versions of software it no longer sells.