If you were under any illusions about Facebook’s market share, then try this statistic for size.
According to comScore, Facebook accounts for close to a third of US ad display impressions.
It was 15.6% in Q1 20101, then 25.9% in Q4 and is still growing, now to 31.2% of the world’s biggest advertising market. Indeed at the current growth rate it is due to hit over 1 trillion ad impressions for the whole year. Facebook run of site CPMs may be low, but even at $1 that would represent a billion dollars!
Perhaps most interesting is how their main display ad rivals, Yahoo, Microsoft, AOL and Google aren’t keeping up, with Yahoo falling from around 12.5% in March 2010 to around 10.5% in March 2011.