The latest numbers from market research firm comScore Networks show Microsoft's Bing search engine rising one-tenth of a percentage point, to 9.4 percent, in U.S. market share in September. That conflicts with a Hitwise report last week showing Bing dropping slightly for the month.

Which researcher to believe? Well, both, in a way. The consistent conclusion that can be drawn from each is that Bing isn't growing at nearly the rate it did in the weeks after its introduction.

That makes sense, given all the attention the launch received. It's clear that people are at least more aware of Microsoft's search engine. The challenge for Microsoft in the coming months, and years, will be coming up with ways to get people to continue trying its search engine -- or better yet, to become consistent users.

Google rose to 64.9 percent in the comScore numbers for September, which have yet to be officially released but were reported on TechCrunch and elsewhere based on an analyst's report. Yahoo, meanwhile, fell from 19.3 percent to 18.3 percent between August and September.