I was just reading David Berlind talking about Tim Bray’s use of Linux over the past couple of weeks (he’s going back to the Mac). I know what keeps me on Apple and Microsoft OS’s, though, and it might not be what you expect.

What keeps me from using Linux? Three things: readability. Fonts. Aesthetics.

Geeks don’t think they matter. But at Gnomedex I could always pick the one or two Linux users out of the crowd instantly. Why? Their fonts looked ugly and weren’t as readable.

Maryam’s new Mac’s fonts are blurry compared to Windows too, but they still are a HUGE advance over anything I’ve seen on Linux.

Why is this? Because font designers like Matthew Carter don’t work for free. One typeface might cost hundreds of thousands of dollars to develop. Even millions. Hinting fonts takes a LOT of technology (Microsoft has at least two teams that I know of working on font and reading technologies).

It gets even worse if you’re Chinese or Russian or Japanese (I hear there’s a few people living in those countries). Why? Their font families take longer to develop and are harder to do. When I visited Bill Hill (his team developed ClearType and commissioned most of the fonts you see in Microsoft’s default pack on Windows) he was raving about his team’s work.

Why is this important? Name the #1 thing you look at most on your computer screen. For me it’s the characters on the screen. If one OS has better looking characters than another (Windows Vista has a whole set of new fonts coming) then that OS will win with most users who aren’t geeks.

This is the #1 reason why Linux hasn’t seen any significant adoption on the desktop/laptop yet.

Fix that problem and you’ll see a serious third competitor for everyday consumers.

But the problem is that Matthew Carter (and other typographers like him) don’t do their work for free. That means Apple and Microsoft will win this game.

The best fonts win.

Oh, and Microsoft, you better hold onto Bill Hill. If he goes to Google then I’ll know Google is building an OS.

Bill told me that the guy who decided to invest in fonts on Windows was another Bill. You might have heard of him. I think that decision will turn out to be the smartest “keep Windows important” move Gates ever made.