Some channels will feature full length streaming video.The episodes rotate by chronology, though keep several, but not always when those series are older.
Many documentaries that have been featured on television since sponsored by channels will also be on these sites. There are also documentary sites that stream videos.
Sadly some of the tv sites that do this practice will restrict it internationally. There have been several UK programs I'd happily watch in this manner.
Many network channels will allow video streaming but you have to sign in indicating your status as a cable customer. Those can load right away by following their security protocols. The Hannibal series could be seen that way, for example, but if you didn't want to do it, then you watch it on a week delay. As I recall The Americans also could be seen in this manner.
Some older films can be viewed on archival websites since there copyright has expired. Night of the Living Dead is one of these.
Youtube has a movie channel to facilitate video streaming, but some videos are free.
Hulu will often show independent films that are extremely difficult to locate anywhere else. They also will show international films as a result of them picking up the Criterion Collection. There's no reason to pay for their service as they rotate it, and you can usually find one decent film of cinematic merit every day. That won't work for lots of international folks though.
Crackle also has both tv and movie streaming and it's free. Sometimes it's excellent but mostly mediocre. I watched Lawrence of Arabia not that long ago.
EDIT: A little tip about Hulu. They have a lot of films, a huge number actually. If you're looking for an obscure but criticially acclaimed film like Chrystal (Billy Bob Thornton), try doing a search. They have that as well as many films that are not featured as scrolling icons, and you might miss the best ones as a result. Sommers Town, a superior charming film from the UK could once be seen on Hulu but you have to dig for it. Sometimes a film can be seen, then they rotate them.
http://www.hulu.com/search?q=chrystal