The question has been kicked around by the technology press for some time now: Why does Google keep products in beta for so long?

Beats me, but I'm trying to find out because the Web monitoring company Pingdom has taken the time to quantify the matter: Pingdom's count shows that almost half of Google's 49 products are in beta, including such established stalwarts as Gmail -- released in April 2004 -- and Google Docs. (Pingdom intentionally left Google Labs out of the mix.)

"Everyone knows Google is fond of the beta label on its products, but we wanted some actual numbers so went through all of Google's products to see how many of them are in beta," Pingdom analyst Peter Alguacil tells me in an e-mail. "It turned out to be a whopping 45 percent. As far as we know, there is no other company that does this to the extent that Google does."

(Update: Google reply below.)

From Pingdom's blog post:

Some products you can understand why they are in beta, like Knol, Google Alerts, Custom Search, Google Chrome, etc. However, a lot of products that you wouldn't really expect are still labeled as beta. Here are a few notable Google products that are still in beta: Gmail, Google Docs, Orkut, and Google Finance. We're so used to seeing the little "beta" tag next to the various Google product logos that we almost don't register it anymore. We even had to double-check that Gmail really still was in beta.

As for early reaction to Pingdom's Google beta count, Vasanth Sridharan of the Silicon Alley Insider writes: "Interesting find, but probably doesn't matter -- Google's 'beta' products like Gmail and Google Docs are about as good as anyone would expect."

I've sent a few questions to Google about all of this. Will be enlightening to see what they have to say.

While we wait, if any of you should have a theory of your own, please share with the group.

(Update: Google public relations tells me that they're trying to get answers to my questions, so that's a good start.)

(Update, 9:15 p.m.: According to a Google spokesman: "We have very high internal metrics our consumer products have to meet before coming out of beta. Our teams continue to work to improve these products and provide users with an even better experience. We believe beta has a different meaning when applied to applications on the Web, where people expect continual improvements in a product. On the Web, you don't have to wait for the next version to be on the shelf or an update to become available. Improvements are rolled out as they're developed. Rather than the packaged, stagnant software of decades past, we're moving to a world of regular updates and constant feature refinement where applications live in the cloud.")