This past summer there seemed to be a lack of Hollywood blockbusters. Many attribute this to the economy, but I think a greater factor is web streaming. Nowadays, people have the ability to watch movies and TV shows for free on the Internet immediately after, and in some cases even before, the movies premiere. And what used to be someone sneaking a video camera into the movie theatre, has become good quality clear copies of the movies and shows.
I remember when Napster first came and revolutionized the music industry by offering free music, then soon movies became available and it changed everything. Thanks to bit torrents and sites like YouTube and Megavideo, people can download movies in minutes and get a relatively similar experience to watching on TV or in the theatre. It's very hard to regulate this type of thing because of the shear amount of websites available and legal technicalities from country to country.
People seem to think that your downloading movies only hurts the actors and movie studios who are getting millions for each film and could use a pay cut. But really, the vast majority of people who work on films are low paid workers who need the film industry to make a living. Other alternatives have come along like Amazon, iTunes, Netflix… who offer movies online at a price a lot cheaper than seeing movies in theatres or on DVD. Still, when faced with the option of a cheap legit movie, or seeing a movie for free, people will always tend to go with the free option.