Yahoo's and MSN's counter-attack on Google

Now Yahoo and No. 3 search engine MSN are about to launch their long-awaited Google counterattack. In May, Yahoo will roll out a revamped technology foundation, including a more robust system of servers and software, followed later this year with improved ways to manage and rank ads. Microsoft Corp.'s (MSFT ) MSN, meanwhile, will go public with its first search-advertising network, dubbed adCenter, in early May. Both efforts offer a peek into the hidden half of the search wars: While Yahoo and MSN may not be able to keep pace with Google's popularity among users, they hope at least to blunt its lead in revenues per search.