Studies show that while Google is still the undisputed master of the internet search market, Microsoft’s six-month-old challenger Bing is steadily growing its market share.

David Karnstedt, the CEO of internet search advertising firm Efficient Frontier, told the New York Times that even though the initial push in Bing advertising is "in the rear-view mirror, [the] fact that they are still showing gains is a good sign." The Times report cites studies that show Bing’s share of online ad spending grew from 4.3 percent to 5.3 percent from the second to the third quarter of 2009, indicating that the new search engine should become that much more of a target for search engine optimization (SEO) professionals.

Microsoft’s recent deal with Yahoo will see Bing used to power Yahoo searches, which consolidates Google’s top search rivals into one website and could provide that company with more competition than it has seen for years. Search engine optimization (SEO) tactics will have to be adjusted to compensate for the shifting marketplace, according to experts.

Search engine optimization (SEO) still aims primarily for improved Google page ranks, but that could well change.