There are whole threads about intentional misspellings for SEO purposes. (If people consistently say "mispelling", hey, let's seed the page with a few of 'em so we float to the surface in searches.) With digressions into google's "did you mean..." option-- or, conversely, their "verbatim search", introduced after reading the searcher's mind became the norm. I have especially fond memories of this one [webmasterworld.com]* in Foo.
* Oh, great. Now the whole WebmasterWorld site will suffer because the phrase "this one" has been used as anchor text leading to any number of different threads [webmasterworld.com]. What to do, what to do.