Been using this feature for a while this weekend. It's pretty useful but a little laborious if you're indexing a full library.
I don't know if there are licensing or programming issues, but it seems like IMDb would be a better fit than Wikipedia. Not all movies have Wikipedia entries. Everything has an IMDb entry. That would also cut down on the non-film-related results in the Wiki searches.
Maybe a choice of either data feed would be a good option?
UPDATE:
I've been using this some more and finding a lot of movies that either aren't in Wikipedia, or that the search refuses to find.
Examples (please don't judge my taste in movies!):
Have a file called "Four Weddings and a Funeral". Search for the full title comes up with entries for nearly every cast and crew member, the movie Notting Hill (and a lot of stuff about popes??), but not the movie Four Weddings and a Funeral. So I try searching for "Hugh Grant Four Weddings". Again, no match for the movie. However, it is the first result on "Andie MacDowell Four Weddings." Go figure.
The Friday the Thirteenth movies also mess up the search. Can't find Parts 2 or 5 no matter what I search for. The other parts, so far, have all been found but are very low in the search results with lots of non-movie related results popping up before them.
Or take a TV special, like the live concert performance of the musical Chess, which aired on PBS a few years ago. I wouldn'et expect there to be a wiki entry for this, but IMDb will have it for sure.
Another advantage that accessing the IMDB database would have is potential for more thorough field mapping, which will probably come in extra handy when I get around to tagging TV series. I think I've seen some open source software that interacts with IMDB, so I'm pretty sure it's possible.