Rated 4 out of 5 stars
It's simple and does what it's supposed to do: It adds a "Search Wikipedia" command to FF's context menu that opens a new tab with the Wikipedia article (if it exists) for the highlighted text.
I just wish it showed the results in a foreground tab, or at least had that as an option. Presumably, if you want to look something up, you also want to see it. :?|