Spell Check and SEO - Interesting article

Found a very interesting article on SEO basic techniques titled Back to SEO Basics - Part 1, Spell Check and Content Analysis, article mainly focuses on why one should perform spelling check and how spelling mistakes can be avoided or tracked easily and effectively. In the last paragraph author Sana Smith says:

"More than 85% people click on "did you mean" link and will get redirected to the exact word search query. So from remaining 15% how much visitors will you get, will that be a quality visitor, and is this worth the effort? You can decide easily."

I'd like to add one thing more here, nowadays google has become even more smart, you will get spelling suggestions the moment you type some wrong spelling in the google search box, thus suggesting correct spellings before you hit the search button. Thus spelling check become lot more crucial. Check the screen shot below if you haven't seen google search spelling suggest till now.