If you don't like the first two opinions, maybe the third time's the charm.

Microsoft 's (Nasdaq: MSFT) Bing grew its market share last month, according to comScore. That report contradicts earlier callsfrom rival Web-analytics specialists Hitwise and StatCounter that found Bing's slice of the search-engine market falling from August to September.

Jaded investors probably aren't going to take comScore 's (Nasdaq: SCOR) word as gospel. They still remember how its bleak readof Google 's (Nasdaq: GOOG) early 2008 performance helped deal Big G a $12 billion haircut in market cap, only to watch the global search leader trounce expectations. To be fair, comScore's assessment was geographically limited in scope, but it's still a top dog in its data-ferreting niche.

It's not just Bing that the analyticoscan't see eye to eye on. Experian's Hitwise had IAC 's (Nasdaq: IACI) Ask.com gaining market share last month, while comScore's findings have Ask and Time Warner 's (NYSE: TWX) AOL clocking in flat for September.

However, Hitwise, StatCounter, and comScore all agree on two things:

Yahoo!'s decline is understandable. Once it agreed to let Bing fuel its searches, the credibility hit was inevitable.

Microsoft had just better hope that comScore, and not the Web watchers that reported last week, has it right. Bing has turned heads since its springtime "decision engine" makeover. If it did lose momentum last month, there are no assurances that it will win any of it back.

We can't call Bing a novelty, because it delivered several months of sequential gains. Honeymoons don't last that long. Its arrival generated legitimate buzz. Conflicting reports probably indicate that it has hit a near-term plateau, but that is all the more reason for Microsoft to ramp up its marketing or see whether it can muscle in with Yahoo!-esque deals for smaller engines. Continued...