Rated 5 out of 5 stars

Excellent tool, provides great insight in technologies used by web sites. Even popular, well-known web sites that are built not to expose such information are often "unmasked" to show what technologies they use.
The only feature it misses is a way to directly show the version of the used technologies at web sites.

This review is for a previous version of the add-on (2.0.9).