A preview version of Google Toolbar (Toolbar 3 Beta) that, when activated, adds links to certain content when the Toolbar finds it on a Web page. For example, an address will suddenly display a link to Google maps, and in ISBN number will link to Amazon. The controversy is just starting, and people are remembering Microsoft's ill-advised Smart Tags program which was humiliatingly withdrawn from the IE browser. the main difference is that Google has little to gain from linking to Amazon, though if course it has much to gain from linking to Google Maps. Company reps are quoted as saying that the link destination will be customizable so that the feature is personalized to the user. Fine. But Google should tread lightly here. True, the engine itself is like a gigantic recommendation engine, but the perception of PageRank as an objective arbiter of destination value saves Google from any stigma. The Toolbar is merely trying to be helpful, but Google has, in the past (Gmail leaps to mind) misjudged and underestimated the power of popular perception. Tread carefully.