Ad marketplaces are bustling

Etology, an online ad exchange, has announced it is now serving 1 billion ads a day in over 190 countries, surpassing competitor AdBrite in the process.

Etology is completely automated for both advertiser and seller. Site owners can determine market value for their ad space, set the price and sell ad packages directly to advertisers, ranging from standard ad units to custom defined sizes.

Meanwhile, Etology's back-end allows advertisers to act as both media planner and buyer, letting users determine what they purchase and where it goes.

AdBrite relaunched last year, with available ad space across 28,000 sites.

Both AdBrite and Etology made good use of the long tail wave, inviting advertisers big and small to promote on thousands of niche sites.