Hulu is an attempt by NBC/Fox/Disney to dip their toes into the waters of online streaming. I appreciate the effort, but in the end, Netflix is a much better service for the price, and plenty of people would just as soon use the free options available instead.
It allowed access to older episodes of some shows (in some cases, the full series was available whereas only the last 5 episodes were available free).
But you still had to watch the advertisments, and the price was on par with Netflix (which made it substantially more expensive before Netflix's pricing switch). Nothing makes $10/month sting like being forced to watch the same advertisment over and over as a 'premium' member. Hulu's advertisements are far less varied than regular television, so I always half-felt like they were going for the subliminal-message-manipulation angle, since I would see the same ad during all three commercial breaks for the same show.
Also, they arbitrarily blocked access from certain mobile devices, which meant that I couldn't always watch it when I wanted to.
In the end, it wasn't worth the money, by a long shot.
Netflix = old content not currently on TV.
Two different uses. If you want to watch current television without cable, you need Hulu.