According to comScore's Video Metrix Report for April, Hulu grew the number of streams it served in April relative to March slightly (from ~380M to 397M) but the unique viewers dropped from 41.56M to 40.11M.
Much of the site’s growth between January and February can probably be attributed to its prime timecommercial, which introduced the site for the first time to millions of viewers. Since then the site has kept up a star-studded marketing campaign to keep awareness up. I suspect that most of the site’s new users earlier this year were the low hanging fruit — people who would love to watch their TV and movie content on their computer screen, but didn’t know that Hulu even existed. Now the site is going to have to convince the die-hard TV fans to switch up their viewing habits if it wants to keep the same momentum going. Hulu Desktop, one of the first products to come out of Hulu labs, may help with this. But it’s going to be hard to break people out of old habits.
I mostly agree with Jason's assessment. Hulu grew rapidly from September to March, taking streams from ~146 million in September to the ~397 milion in April, while growing unique users from 12.5 million to 40.1 million in that period (with a peak of 41.56 million in March). It's hard to sustain that sort of growth and the audience of people. The good news is that overwhelmingly, most people (name the demographic, and it's probably still true) aren't checking out Hulu even once a month, not even for a clip, so there's a LOT of room for growth. The bad news is that overwhelmingly, most people aren't checking out Hulu, even once a month.
Lots more, including data tables on TechCrunch