"Similar to the navigational suggestions, sometimes we detect that the most relevant completion for what you're typing is an ad. When an ad is shown, we mark it with the text "Sponsored Link" and a colored background, as on the results page."
The updated Google Suggest will have an interesting side-effect: you'll see the search results pages less often. Google saves you a few clicks by suggesting search results directly from the homepage, much like Google Chrome's omnibox, but monetizing the suggestions seems out of place. The ads draw attention from the list of suggestions, they're unnecessarily large and they clutter the interface.
Hopefully, Google won't show sponsored links in the list of suggestions very often and Google will focus on adding useful suggestions like: unit conversions, results from Google Calculator, facts etc.
Side notes:
* I don't see the ads in Google Suggest, so maybe the feature hasn't been publicly launched yet.
* Is this the first time when Google shows third-party ads on the homepage?
