[johnjhayes]

The only thing I haven't seen is this. Ok, using the clickstream data is an established practice, but does Google use clickstream data from users making searches on OTHER search engines, or just their own?

This is the crux for me, Bing is using data from Google, does Google use data from Bing or only themselves?

Even if all true, I don't see it as unethical business practice. Definitely a marketing black eye, but not much else.

[spot]

The information flows one way, from Google to Bing.

Google is careful not to do this.