Tracking/targeting software for commercial sales.
Go ahead and sign up.

Not sure what you mean by that?
Ghostery is now owned by Evidon (they used to be called The Better Advertising Project). Only if you opt in will the software send stats to Evidon which in turn sends them on to the BBB and the Direct Marketing Association. They use the stats to keep and eye on online advertising companies and report them to the FTC when needed.
It got 5 out of 5 stars from CNET editors and a good write up from privacychoice.org.