The search engine deal rumored for some time is now official with Microsoft and Yahoo announcing a partnership which they say "will improve the web search experience for users and advertisers, and deliver sustained innovation to the industry" and may factor into the search engine optimization (SEO) strategies of online marketers.

Under the new pact, Microsoft will power the search functions of Yahoo, while Yahoo runs the sales for the new venture.

The deal gives Microsoft a foothold in its effort to become a major player in the search engine world against Google.

According to figures from comScore, Google still dominates the search engine market with 65 percent of search traffic in June. But the new deal would give Microsoft increased leverage with almost 30 percent of the market.

In announcing the deal with Yahoo, Microsoft CEO Steve Ballmer said the new partnership gives people a choice beyond Google.

"Through this agreement with Yahoo, we will create more innovation in search, better value for advertisers and real consumer choice in a market currently dominated by a single company," he said.

The companies expect the deal to be finalized early next year, but it must still be reviewed by industry and government regulators.