zjacob - 10:24 pm on Nov 15, 2007 (gmt 0)

There's plenty of great stuff in that article:

“Google had already understood how to match keywords with URLs, so the next step was building a matching algorithm and create an advertising system around it. Sergey had a mandate to launch it in June 2003. So we had less than six months.”

and

“When we started AdSense, it was just me and four engineers,” Rajaram says. “The night before we launched, Sergey spent five hours with me testing the system and pointing out bugs.”

Given that information (four engineers & one product manager & six months), HOW is it possible that Microsoft, Yahoo! and others (yes that means you Ask.com) find it so hard to launch a copycat system to Adsense?