Within the last 24 hours, Yahoo! search results have been supplied by Microsoft Bing. This is a unified attempt between Microsoft Bing and Yahoo! search to take on Google.
Last year, Microsoft and Yahoo! agreed a 10-year web search and advertising partnership in an attempt to close down the share market which is currently dominated by Google. Yahoo! currently sit in second spot, ahead of Microsoft.
USA users may already be aware of Yahoo! showing Bing results, with the 'Powered by Bing' notification at the bottom of Yahoo! search results. Yahoo! continue to control how results are presented.
As it is now showing Bing results, Yahoo! no longer supports link commands such as linkdomain:. With Microsoft dropping theirs years ago, and Google supplying unreliable data, the top 3 search engines no longer provide users with link information. This opens a door to third-party software, such as Majestic SEO.