Marin Software published a report last week ("Why the Search Alliance Is Paying Off for Paid Search") which suggests the Microsoft and Yahoo search alliance increased the share of paid-search impressions by 4% and share of clicks by 2%. Consequently, Google's share declined by the same percentage according to Marin.
According to the report, Microsoft and Yahoo saw paid-search share of impressions rise from 19% to 23%, and paid clicks rise to from 19% to 21% in the first few months after the alliance went into effect. Marin's VP of Marketing, Matt Lawson, said in the report that he sees the drop in Google's ad share as an opportunity:
"We know Bing can potentially close the gap, as advertisers come on or rejoin the new platform," he says. The search alliance has resulted in improved traffic quality for advertisers. Higher conversion rates demonstrate improvements. Excluding the impact of seasonality, conversion rates rose by 12% during the study period. The results show that consumers respond to the combined platform."
Marin's study concluded that conversion rates on the search alliance became more favorable following the transition. Marin attributes this to several factors including higher-quality traffic, better targeting options and a more efficient marketplace.