SearchIgnite and RBC routinely partner to release insights on market share and revenue per search of Google, Yahoo and other players in the search space--using spending data from more than 500 marketers (all of whom are clients of SearchIgnite or sister search firm, 360i).

This quarter's study, entitled "Summer Heats up for Yahoo," tracked impressions and clicks across Yahoo, Google and MSN from January of 2006 through the end of September 2007. Yahoo releases its quarterly earnings this afternoon.

The research found that advertisers were spending more in Q3 than Q2--and that they were more apt to put those extra dollars into Yahoo, as Yahoo's percentage of incremental media spend increased by 7.8% in Q3.

The Web giant's uptick was buoyed by increases in July and August (and slightly tempered by a dip in September). Meanwhile, marketer spend on Google dipped in July and August and jumped back up in September--but overall spending on a same-client basis only increased by 0.8%.

It's not a seismic shift--as Google still retained a more than 70% share of search media spend in Q3, compared to Yahoo's roughly 20%. But according to Roger Barnette, president of SearchIgnite, the shifts in incremental spending represent a definite opportunity for Yahoo to gain market share--if the Web giant can continue to deliver valuable, more cost-effective clicks and impressions in the eyes of search marketers.

"This is not saying that Yahoo severely eroded market share in terms of media being spent--but the increase in incremental dollars was remarkable over the short term," said Barnette. "In past quarters, if clients had extra dollars to spend, they almost always went more to Google than Yahoo. But in Q3, the vast majority of those dollars went to Yahoo--and it's a positive trend that if sustained, could help them gain meaningful market share."

Yahoo also saw improvement in share of overall media spend in Q3 07--inching up by almost 2 percentage points--the first reversal of overall share since the Web giant's Panama-related boost in February. In addition, Yahoo's quarter-over-quarter share of impressions lifted by more than 6 percentage points.

Meanwhile, a closer analysis of Google's share of impressions--specifically from August to September--yields insight into where search marketers' views of Yahoo's superior ad performance could have stemmed from.

Google countered the "summer search slump" by delivering 62% of all search ad impressions in September--an increase of nearly 8 percentage points from August--but the increase was flanked by almost an entire percentage point drop in click-through rates.

Whether search marketers will continue to funnel their incremental search dollars into Yahoo in the hopes of better-performing ads or lower CPCs remains to be seen--as Q4 will yield insight into whether recent changes to the Web giant's algorithm and the launch of features like Search Assist cause an increase in overall search volume and user retention.

Insiders say that if Yahoo's Search Marketing business is any indication of how the rest of the company performed in Q3--then Tuesday's earnings call could yield better numbers for shareholders than Q2's.

"The view of Yahoo that we have access to isn't the only thing that affects their stock price, but the search marketing piece of their business seems to have a lot more momentum than last quarter," said Barnette. "If it's a bellwether for the rest of the business, then the Q3 earnings reports could be a pleasant surprise."

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