Buck, I don't know which site you're referring to. As I noted above, the only legally available material falls into either category 2 or 3 above, whether it's streamed or available for download. The fact that it's streamed (remains on the server) doesn't inherently make it legal.
If it's a recently released (commercial release) movie that you'd either have to go to the movie theatre to see or rent a DVD or pay for at the iTunes store and it's being streamed for free on some site, you can bet that it's NOT legal. If it's a recently released movie that is still in the movie theaters and hasn't even been released to DVD, then you KNOW it's illegal and that the streaming copy has been obtained by either recording the movie in a movie theater with a video camera (yes, people do this) or it's a completely illegal copy of a reviewer's DVD or similar. Either way, it will be low-quality, low res.
Usually, you'll find that streamed new movies are rapidly removed from the servers; the host sites turn a blind eye until someone demands removal. They tend to have terms of service that SAY they abide by all copyright laws etc., but it would appear that this is true only if someone's keeping them honest. I wouldn't be surprised if the movie distributors have teams of people who do nothing but root out all the illegal downloads popping up all over the place every day like a so many bad mushrooms. And that goes for both streaming and downloading.
