No, if you are the producer, writer, actor, and music composer, or if you own free and clear the rights to stream the movie on-line. baring that yes, it is illegal and there are monetary and possible jail penalties.
BTW, No difference with downloading.
USPTO Registered Patent Attorney, Master of Intellectual Property law, MBA I am neither your attorney, nor my answers or comments in AVVO.com create an attorney-client relationship with you. You may accept or disregard my free advice in AVVO.com at your own risk. I am a Patent Attorney, admitted to the USPTO and to the Florida Bar.
I assume you are asking whether you are doing anything illegal when you watch an illegally made copy of a movie (without yourself making an actual permanent copy) as opposed to if you actually downloaded a copy. No difference as far as your liability. In fact "streaming" creates a temporary copy. Your act of streaming is an illegal performance of the movie. There are many different exclusive rights under copyright law so there are no loopholes...one of them will always get you if you are getting something for nothing.
This answer is not legal advice nor should it be construed as such. I always attempt to provide factual information relevant to a question, but, in the end no attorney can properly advise a potential client based on the limited facts that can possibly be disclosed in a format such as this one.
Q: "Is streaming movies online illegal?"
R: Really? You want to know whether you may lawfully transmit a movie out onto the internet so that the world's 2.4 billion people with internet access can view it? Without the permisson from, or any compenstation paid to, the movie producer? Do you own the copyright in the movie? No? Then why on earth would you even entertain the thought that you're allowed to transmit the movie worldwide?
The above is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.
If you mean broadcasting the stream then Yes if you own the copyright or have permission of the copyright owner. No if you do not.
If you mean receiving a stream, yes if you and/or the broadcaster sending out the stream owns the copyright or has permission and NO if neither of you does.
Sending the stream is distribution under 17 USC 106 while receiving the stream is making a copy, just more temporary than a normal download.
If you are asking is it less risky to steal copyrighted movies by streaming, the answer is yes a technology and law has yet to fully catch up to streaming the way it has on torrent file sharing, gnutella file sharing, etc. However, the MPAA and RIAA are hard at work to find a way to track it and mail offenders, so the catchup will surely come and you should not be on the wrong side of the law when that happens.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.