According to Yahoo! Search blog, the company is attempting to take advantage of user-driven indexing of images in order to integrate images into web searches. User indexing has been done through tagging on Flickr, and Yahoo! now shows Flickr images in some of its web searches.
What happens is that when a user writes a search term that includes words like photos, photography, pictures and the likes, the first line is photos from Flickr. For example, Yahoo's search results for the term 'interesting photos', brings the following:

While this is a small test, the possibilities are interesting. Yahoo! doesn't have any ads at the moment in its regular image search (I believe Google doesn't either), probably because most times the images are either useless or irrelevant. However, having Flickr photos in its regular web searches will probably bring better results to such image searches because of the tagging, making ads more relevant.
Yahoo! Inc. shares closed at $28.99, up 29 cents today, or 1.01%.










