Some stalwarts in online display advertising had rocky first quarters. Microsoft’s overall ad business was up 9 percent, but that was because an increase in search overcompensated for a decline in display. The New York Times blamed About.com (down 23 percent) and macroeconomic trends for its overall 10 percent decline (2 percent down outside of About). But that decrease was worse than its print shrinkage. And it’s hardly the first time that online advertising has been affected by seasonality or a tough economy. Earlier, Yahoo display revenues were down 4 percent. Maybe these companies are just losing share. Google said its display growth was “robust” and on a $5 billion run-rate. Let’s see how AOL and Facebook do before panic sets in.