A lot of people seem to believe that Google Inc. can rule any market segment it wants. Hype meters have gone haywire assessing the search company’s expansion into such far-flung fields as financial news and wireless Internet connectivity.

Reputation aside, however, Google isn’t always a category killer. Consider the thud made by its late-entry instant-messaging application, Google Talk. This is why I’ve found Google’s free program for searching computer desktops a fascinating study.