>I don't see how Evidon is under any obligation to explain exactly what analyses they perform on the data or what the companies they sell it to do with it.

Given that Ghostery provides a service that blocks companies tracking data, it has every obligation to explain why it's Ghostrank program is any different from the very thing you are expecting them to protect you from.

Otherwise, it is like a sugar substitute that makes you fat anyways. Theoretically there is a legitimate use case (insulin dependent patients) but for their average customer (people who want to loose weight) it is borderline fraud.