A few day old article on Techcrunch, Online Advertising Revenues Jump Almost 15 Percent In First Quarter , on how online advertising companies revenues went up 15% in the quarter, but worth asking the question...

For myself, I did see eCPM for my collection of sites/niches running Adsense rise 4.2% for April from the previous month. Split out the niches and some stayed the same with the increase coming from the health and Green niches.