great addon Rated 4 out of 5 stars
Fantastic functionality. Never have I been less observed on the internet! It is great that Ghostery takes a pro-active approach to thwarting the scum of the internet who make a living off spying on you.
So far as I can tell the coverage of Ghostery's blocklist is quite good and regularly updated.
The only downside to Ghostery is its impact on Firefox performance; as about:memory indicates, Ghostery normally uses twice the memory that Adblock Plus does even though ABP has a much larger database. Normally at least 10% of Firefox's total memory is used by Ghostery, which is a very substantial amount (100MB+ when Firefox is using 1GB). Unlike ABP, Ghostery's memory usage grows with the number of tabs open/time Firefox has been open. It is possible some of this memory is offset by having fewer trackers embedded into the page, but clearly memory usage is an area that could use some development effort.