Johnson & Johnson ( NYS: JNJ ) beat analysts' earnings expectations yesterday and raised the lower end of its 2011 earnings guidance, but traded down for most of yesterday until the late-day rally. And it's down a few points today while the Dow Jones (INDEX: ^DJI) has been relatively flat. What's going on? As best I can tell, investors seem a little anxious about the revenue number. Sales came in just under analysts' expectations, and more than half of the 6.8% year-over-year increase in revenue came from changes in exchange rates, which boost international sales but can't exactly be counted on. Stateside sales were actually down 3.7%. While I'll agree that revenue is important, beating on earnings with "weak" revenue isn't that bad for a conglomerate like Johnson & Johnson. By definition, it means net margins came in better than analysts were expecting. Expanding margins has been Johnson & Johnson's shtick for much of its 125-year existence. The declining sales in the U.S. aren't something to fret about, either.