Googl, Googel - How search engines handle misspells

Everybody misspells when searching for information. Either it's because you're in a hurry, or because you really don't remember the exact name, you're contributing to the large number of misspelled word searches that make engineers behind search engines like Google, Yahoo or Live think of better solutions to return the results you intended to find in the first place.
I'm starting with the conclusion, but Yahoo and Live Search handle this better than Google.

How Google handles misspells
Whenever you do a search on Google for a misspelled word it will show you at the top a suggestion, based on a broad match it's doing between your search and its database. Example, searching for any of the following misspelled words will make Google suggest you to search for the best match it found (Did you mean: Google): googl, googel, goggle, goole, gogle, googles, gooogle.

This way it gives you the option to choose whether you want to search for what Google thinks you meant to search for. This is a good way to check your spelling too. If you don't know how a word is spelled you can search for it in Google and you'll also get a suggestion in case the word is not spelled correctly.
Google does its best to try to avoid showing how popular some misspelled word searches are. For instance, one tool that Google provides is the Google Suggest service. As you type, Google Suggest will show you up to ten other similar popular searches that people did. However, if you try entering a misspelled word, Google Suggest will show you the corrected word in the suggestion box. Try this, go to Google Suggest and type in Googl and after that a space. You'll see that the suggestions are all for the correct match, which is Google:

Now this doesn't mean there aren't ways to find the popularity of particular misspelled words using Google. A remarkably useful tool for marketers is the Google Adwords Suggestion tool, which lets you search for words (and their synonyms) and sort them by their search popularity.

How Yahoo Search handles misspells
When you enter a misspelled word in Yahoo Search, Yahoo will automatically show you the results page for the corrected word (what it considers to be the best match) and gives you the option to show the results for the misspelled word. So say you are searching for yaho, it will return you the results page for yahoo which is the corrected word but lets you also search only for yaho if you either put a plus sign in front of it (like +yaho) or clicking the word in the message that informs you what it searched for:

While this is a better approach than Google's, Yahoo will also let you know the popularity of particular misspelled words. For instance, doing the same search for Googl on Yahoo (unlike Google the suggestions are shown by default as you type in Yahoo):

As you can see even as you type goog, it will suggest you that googl and googel are other popular misspellings (suggestions are shown based on their popularity).

How Live Search handles misspells
Live Search doesn't have a suggestion service (like Google suggest or Yahoo suggest), but it behaves in the same manner as Yahoo does when you're entering a misspelled word/phrase as a query - it will show you the results for the corrected word, but also gives you the option to show the results for your misspelled word (same test using the googl keyword):

So, the ideal behavior for a search engine in this case would be to return automatically the results for the corrected word and to give you the option to search additionally for the misspelled one (just like Yahoo and Live Search do), but also the suggestion service should exclude the misspelled words (like Google Suggest does).