Reason?
Google Auto-Correcting of Queries has started!
The Google Operating System blog reports that Google now automatically searches – or at least highlights – spell-checked versions of some search queries. As an example, when you search for christine aguilera, Google will not show you a “did you mean?” box, but show you an embolded “christina aguilera” anyway (at least sometimes*).
Source:
http://blog.outer-court.com/archive/2007-01-16-n11.html