Recently I've noticed that some sites I'm tracking for sets of keywords appear in their misspellings, however when the keyword phrase is correctly spelled my site is gone. For example at the time of this post if I search for this, notice this misspelling on the "expatraites" it shows my site #2 (china-health-insurance.com). However when I search for the proper spelling here my site is bumped down to #22. I checked my site for the misspelling however I came up negative. I'm guessing that this is Google's way of testing sites for user interaction. They place a site on a less competitive (misspelled) keyword phrase to test its click through rate. Any other ideas?
I've noticed this myself when looking in my refferer logs I can see typos in peoples search terms. I've no idea why we are ranking different for them. I would have thought google realises what word they are trying to search for, but like you I am ranking differently for the wrongly spelt version. Its weird.