On a global basis, we might already be seeing a recovery, at least for search advertising. The online advertising revenues of the four largest Web advertising companies (Google, Yahoo, Microsoft, and AOL) increased 1.2 percent in the fourth quarter. Google accounted for all of that growth, however, so we are still waiting for display advertising to find its footing.

It is likely that in the U.S. alone, search advertising is also leading the recovery. But now that Google is mixing more visual elements into search ads (are those display or search ads?), perhaps display ads will see a boost as well.