I sold an image today and decided to check other images in a similar vein, namely those related to the crisis in the Eurozone and in Greece where there is voting tonight on the bail out terms and conditions.
With keywords euro mouse trap 73 images appeared
With keywords euro mousetrap 103 images appeared and perversely in my view using keywords euro trap mouse mousetrap only 59 images appeared.
My view is that it is sensible to check the major keywords; clearly mousetrap as one word has a different response to mouse and trap

This discrepancy has the potential to lose significant sales.