The Google toolbar includes a component that allows Google to keep track of which sites you click to from a Google search. This means that when you install the Google toolbar, you "volunteer" to be a "reasearch subject" to help them compile statistics that they need in order to get the sites people want to see first on the list.

In order to know what the "tracking element" of the tool bar does, you have to read all of the "disclosure document" that they make easily available. This includes about 80 pages of fine print (I printed the main document once) and an additional similar amount in half a dozen supplemental disclosures that are "incorporated by citation" in the main statement.

I have read all of them, and I don't find anything that is objectionable to me. They provide a service that I find helpful, and the "tracking" that they do appears likely to be, and is limited to, information that they can use to improve Google. It includes only statistical information on the use of Google without any "personal identification" of the users from whom the information is collected.

There is always the possibility that "they lied" and might collect additional information, or might make "surreptitious" use of what they collect. Some other "reputable(?) sources" have done some pretty shady things (AOL and Yahoo come immediately to mind); but the complete disclosure that is available from Google gives me reasonable confidence that they are doing what they say they do.

I don't find it objectionable, but you should be aware that installing the Google toolbar does constitute your agreement that they may collect statistics on what you do with it.

John