Google Inc. (NASDAQ: GOOG)'s acquisition team operates on most days under the radar, as the Web company receives recognition for billion-dollar acquisitions like YouTube and DoubleClick. But there are dozens of other small start-up acquisitions that go unnoticed. Count GreenBorder Technologies among that group, as Google has quietly acquired the company while doing away with its products at the same time. Say what?

GreenBorder makes a security tool that allows the Web browser on your PC to stay mostly isolated from the hijack attempts and bad, malicious software that some website owners want to install on your PC without you knowing. Sure, there are software products that do this already, but the difference is in the way GreenBorder's product actually isolates the browser from the ties into the operating system. Result? A much more secure product.

Why would Google make an acquisition like this? Think about this: Google could not survive without Microsoft Corp. (NASDAQ: MSFT). Eek! But it's true -- Microsoft's Internet Explorer browser is still, by far, the most-used Web browser on the planet and Google's entire revenue existence resides inside that browser (instead of software installed on your PC). Billions of dollars in Google revenue happen each quarter using Microsoft's Web browser as the enabling conduit (along with other browsers like Firefox, Opera and Apple's Safari). Google has a vested interest in making the browser you use as safe and functional as possible at all times. If not, Google's revenue train comes to a screeching halt.