Doqume (http://doqume.com) It's a way to search text documents by specifying complex semantic conditions on items that have to be matched instead of simple keywords.

I think it's interesting because 1) it is challenging and it involves a lot of NLP (which I like) 2) I believe it's novel or at least I have not seen the same concept around.

Whether or not it is actually useful to somebody remains to be seen...