Why is Google so hysterically hypocritical about Bing using its public data? — RoughlyDrafted Magazine:

Install the Google Toolbar and do a search of Bing, and Google actually directs your clickstream back for its own analysis. And really, that appears to be all Bing is doing, as it offers a similar option to record users’ behaviors and upload it back to Bing to improve its results.

It's a strange, new, data-mine stealing world.