It's a frequent, anxious query, made as the questioner looks over his shoulder at the shaky mortgage market: Are we in another technology bubble, one that will burst with the slightest jar? I'm sure we're not, but it's hard to explain why.Something fundamental has changed in Silicon Valley's technology speculation streak. Back when we were partying like it was 1999, building a Web site and getting traffic was enough. Today, the money pouring into new technology is more cautious, more knowledgeable. Granted, eBay's purchase of Skype for $2.6 billion is tasting a little sour. The company just took a $1.4 billion charge in its third quarter related to the acquisition. Skype generated traffic; it added 160 million users over the last two years to reach a total of 220 million. But that traffic has yet to pay off for eBay.

Sound like the dot-com era all over again? Well, instead of going out of business, Skype remains very much an ongoing concern, the most successful VoIP provider on the planet. And the loss is being taken by a mature Internet company, one of the few that can bear it. Don't look at eBay's write down as evidence of a bubble. Look at it as a wealth transfer mechanism from the mature to the youthful entrepreneur. EBay may yet figure out how to get a return on its investment.

How about those reports, related last week in the Wall Street Journal, that Microsoft is negotiating for a 10% stake in Facebook. It's reportedly willing to pay $300 million to $500 million, which places a valuation on Facebook of $6 billion to $10 billion. "It is such a large amount that it makes me suspect that we're in the run-up of another bubble in Internet company values," warned David Bradshaw, analyst at the Ovum technology market research group.

But I would say the same rule applies as in the eBay case. If Microsoft invests $300 million in Facebook and the investment doesn't pay off, what does that say about the technology market? It says a mature company, that can afford to lose $300 million, took a calculated risk on social networking. Maybe it loses some of the money. Maybe it learns something about how Internet crowds flock together and engage in social collaboration. This kind of bubble isn't keeping me up at night.

The principal way for startups to exit the market for at least three years has been through acquisition by a mature company, not through an initial public offering. IBM, Oracle, SAP, Sun, Cisco, and Microsoft have all been letting their venture capital research substitute for their internal labs research, and who's to say the return isn't just as good or better. A successful IPO, such as VMware's, is all the more notable in such an era.

As they buy up small companies, these companies get some measure of marketplace feedback on what works and what doesn't. That's worth a lot in this era of rapid change. There's a lot of pushing and jostling around startups these days and, for some reason, the "bubble" around them just gets a little bigger.