I was really excited by this writeup, so I tried it. Four test queries returned nothing that seemed useful or even relevant:

fluid dynamics + electromagnetism : expected magnetrohydrodynamics, got Maxwell’s equations and classical mechanics (not useful);

verse + 5 - rhyme : expected blank iambic pentameter, Shakespeare, etc.: got nonsense;

writer + American + Russian + Great - Nobel Prize : expected Nabokov, got Meirkhaim Gavrielov + 1 nonsense result;

plant + illegal - addictive : expected cannabis, chronic, etc; got “Plants” (thanks) and “Nuclear Weapon” (?!? ) and some Hungarian village.

EDIT: I thought maybe I wasn't being sufficiently imaginative, so I tried "Nixon + Clinton - JFK" and got nothing that looked interesting. Then I noticed that the "Nixon" part of my query was "disambiguated" to something like "non_film", and the word "Nixon" was just stripped out. I think this thing is just broken.