Gbrowser - efficient cloaking detecter?
Maybe it is.
If it is, then member brandboerge raises a very good point:
Depending on the user agreement, they could report more data from each page. They would have enough data to implement statistical algorithms that could make it possible to distinguish between cloaking and ip-delivery for "honest reasons". And if the browser itself were faster than Internet Explorer, they could spend some milliseconds for uploading and comparing pages (not images though) without the user noticing.