Comparing the European online advertising market to that in the US, you could say that Europe is about two years behind the US. But then you have to ask the question, are we talking about all of Europe, just Western Europe or a specific nation?

Behind search advertising's great success is self-targeting — users revealing their interests by the keywords they enter. As with search, self-targeting rather than media manipulation is the key to engagement marketing or behavioral advertising.

In fact, in 2009 or 2010, I think Yahoo is the stronger company. I think the general media consumption favors them.

The spending growth is impressive, but shouldn't come as too great a surprise. These dazzling increases are possible in part because growth came from such a small base. And in the last few years the Internet has truly become a mainstream medium.

Behind search advertising's great success is self-targeting — users revealing their interests by the keywords they enter. As with search, self-targeting rather than media manipulation is the key to engagement marketing or behavioral advertising.

The growth will be driven mainly by search.