MSN is still struggling against Google and Yahoo! in the high-stakes search business, and seems to have lost some ground recently, according to research reported today by Nielsen//NetRatings.

Comparing March 2005 with March 2006, Nielsen found that searches on Google and Yahoo! grew 41 percent and 47 percent, respectively, while the overall number of searches grew by 36 percent. In other words, Google and Yahoo! outpaced industry trends. MSN grew by only 9 percent in number of searches.

Google's market share increased by 2 percent to account for 49 percent of all searches. Yahoo! 's share climbed by 1 percent to 22 percent. But MSN's share dropped from 14 percent to 11 percent.

It's a poor showing, and one that will weigh heavy on the minds of Microsoft executives next week at the MSN Strategic Account Summit. MSN is hosting the meeting to give a rundown of its technologies for marketing and advertising executives. We'll be there covering it.