Google Suggest Preparing for Global Launch:
Google France's homepage tests a query suggestion feature based on Google Suggest. The feature seems to be enabled only for the homepage and there's a setting that lets you disable it. In March, other people noticed Google Suggest enabled by default at Google.com.
Launched in 2004 as part of Google Labs, Google Suggest is available in many interfaces and in some international Google sites:
* Google Labs
* Google Experimental Search
* Google Toolbar for IE and Firefox
* Firefox 2+ search box
* Google's homepage for iPhone
* Google China, Google Korea, Google Russia, Google India
* YouTube
You can even use the suggestions in your applications thanks to the unofficial JSON API:
http://www.google.com/complete/search?hl=en&client=suggest&json=t&jsonp=CALLBACK_FUNCTION&q=QUERY
Similar suggestion features are already available at Yahoo and Ask.com. Yahoo's suggestion feature called Search Assistant is more advanced as it displays popular queries that contain your keywords, not just queries that start with your text.