Calendar company Trumba gets $8 million. Yep, it’s crowded.

Trumba, a Seattle start-up that lets you share your calendar with others online, has raised $8 million in Series B funding, according to PEW (scroll way down).

But with Silicon Valley companies like Zimbra (which has raised $16M), AirSet ($2M internally) and others (we met yesterday with someone who is eager to launch) now in this space with free products for individual users, we’re wondering why Trumba thinks they can get away with charging $40 a pop per year? Even if you do pay, you wouldn’t be able to…

share with others — unless they pay too. Tough proposition, as our colleague Langberg said. Or is that why Trumba raised $8 million — so they can afford to give it away and make money some other way?

Anyway, Trumba’s investors in this round include Oak Investment Partners, and existing backers August Capital and Kleiner Perkins.

Airset, by the way, told us they planned to raise outside capital after generating some revenue, which they predicted would be late-summer with the release of a mobile software version (btw, you’re hosed if you’re a start-up and don’t have a mobile version these days). So perhaps we will hear from them soon too. Airset is based in Pleasant Hill, on the northeast fringe of the Bay Area.