New search engine data from Experian Hitwise show that Microsoft’s Bing search engine has increased its market share for the third month running, indicating that the target surface for search engine optimization (SEO) could be gradually becoming more competitive.

The Experian data show that Bing’s market share grew 4 percent in month-over-month terms to finish at 9.7 percent, while still-dominant Google dropped a point to finish at 70.95 percent. Between those two, Yahoo remained steady at 14.57 percent.

Experian also notes that searches are gradually becoming longer, saying that the data indicate a drop-off in one- and two-word searches and increases in searches of three words or more. Two-word searches became the most common queries, however, edging out single-word searches by 0.04 percent.

While Google is still far and away the most used search engine on the internet, Bing’s gradual but consistent growth coupled with pending completion of that search engine’s integration into Yahoo’s main search portal means that Microsoft could soon be providing Google with meaningful competition for the first time in years, experts say.