Hey kids! Want to start a company? Why not two, or three, or eleventy hundred?

Forget focusing on one thing for years and working hard to make it successful. That's so old media. Nowadays, if you're not working on at least two startups, you're just out of it. Take Digg cofounder Kevin Rose: He's also got Revision3, an online-video startup. The San Jose Mercury News recently examined the conflicts Rose faces in running multiple startups.

And then there's Evan Williams, the creator of Blogger, who's using the money he got when Google bought his first company to buy back Odeo, his second company, from his venture-capital investors. Williams himself admits he screwed up Odeo, and recently, his attention has wandered to Twitter, an Odeo spinoff. Now he's creating Obvious Corp. as an umbrella for Odeo, Twitter, and other projects, arguing that the Internet business is increasingly hits-driven, so it makes sense to have multiple projects going at once.

We can see that argument for financiers, who need to spread their risk. And if the Internet business is hits-driven, maybe the new model is Hollywood, where studios back multiple projects at once. But you don't usually see directors and stars filming multiple movies simultaneously. You get one movie in the can, and then you move on to the next one.

Williams, of course, is using his own money to back his multiple-startups theory, and says he's just in it to have fun. Well, all right then. But we'd point out to would-be imitators that if your goal is to have fun on the job, don't count on getting other people's money to do it.