Will Display Ad Slowdown Crimp Yahoo and AOL?

Earlier today, Valueclick (VCLK) warned that results for the second quarter as well as the rest of the year will be below previous expectations, putting at least part of the blame on a slowdown in online display advertising. That raises some serious questions for other companies with significant exposure to online display ads, in particular Yahoo (YHOO) and Time Warner’s (TWX) AOL unit.