Powerset hasn’t even started competing with Google yet and already it has its own competitor.
Digger – which is currently in private beta – does sense disambiguation of the search terms like everybody else. Unlike everybody else, however, they expose the underlying WordNet definitions to the searcher and allow them to pick, rate and even discuss the senses a la Digg or maybe Search Wikia concept.
This probably will not appeal to the casual in-and-out user, but I could see how searchers in niche areas could spend time contributing and clarifying the senses to get better search results in the future. This, of course, makes the search engine more sticky to those people in the long run as well as making it more generally useful. Hopefully, they would also contribute back to the WordNet project itself.
I have requested a beta account and will do a more detailed review, if I get it.