We took a look at “Market Share” of the three big search engines and saw some interesting trends.

A few notes on the data:

• The benchmark we used was advertising expense; not impressions of traffic volume.
• We looked at Paid Search only, not content or banner deals.
• We studied only the advertising network, not strictly the engine’s domain.
• Our systems are engine agnostic: Our clients do not set engine budgets; with most of them having no budget at all. Based strictly on, where traffic can be purchased within efficiency tolerances, they allow money to flow.

Given that understanding, here’s what we saw over the past 15 months:

Three observations instantly catch our attention:

• It appears that since last August, Yahoo! has regained some ground.
• Google seemed to get a far larger holiday kick than the others.
• Even with its cash back offers and willingness to buy Market Share from Google, MSN failed to make its presence felt. I’m sure others saw Google ads for Live Search on high traffic KW, yes?

While the last two observations are not that surprising, the first one has definitely pushed us to keep a constant track on further developments. It’s probably going to be a story with lots of sudden twists and turns.