At the alltheWeb.com page, you can see a message that says, “Yahoo! will be closing AlltheWeb on April 4, 2011, as we focus on other features to improve your search experience. Starting on April 4, 2011, http://www.alltheweb.com will redirect to Yahoo! Search at http://search.yahoo.com. Thanks for your understanding.”
AlltheWeb once used to be a favorite of many webmasters, an upcoming search engine who could compete with Google, back in the day. It was acquired by Yahoo! in 2004 by acquiring Overture (who acquire AlltheWeb). Yahoo had bought Inktomi, AlltheWeb and Alta Vista some time back in 2004, to stop depending on Google. After the acquisition, Yahoo! made changes to both the search engines, AlltheWeb and Alta Vista, adding their own search technology to each.
Now, come 4th April (Microsoft's birthday) and it will be an official demise of yet another great search engine, loved by webmasters for what it use to do, the way it used to do. AlltheWeb.com will redirect to Yahoo! Search which is powered by Bing, and which is owned by Microsoft.