Official Google Blog: Spelling For Muggles
When I do not have much time to go through the dictionaries to find out the proper usage of words of phrases, I try this option as well. I run a query in Google with a sentence with the spellings or arrangements that I am not sure about. Obviously my intention is to see the Did you mean: part. It helps me a lot and saves my time as well.
However, if someday more and more people start using wrong spellings then the system would be in danger. If, one day, 90 among 100 type "soker" instead of "soccer" then those who typed "soccer" would be prompted a message Did you mean: soker. I am sure Google would find out some way and save soccer :grin: