listen to it? Please, no "do it anyway" dumb answers - I'm seriously curious about this.
If I play one of my cds on my car radio for a friend, there's nothing illegal about that. If I play it for a friend over the phone, same thing - no problem. So how about I email an mp3 and invite the friend to listen? It would seem that there is no difference UNLESS the friend chooses to keep the mp3. That is, listening to it doesn't seem to be the problem, it's when the recipient decides to add the mp3 to their personal collection that the law is broken.
For example, amazon.com's terms of service seem to restrict the transfer or redistribution of digital content. And it wouldn't seem that "here, listen to this" represents a transfer of the content UNLESS the recipient actually attempts to keep it for their own personal use.
I believe the copyright statements usually say "NO illegal copies even IF not for monetary gain"?? So If you're copying the file and emailing it to your friend, TECHNICALLY, yes that's illegal. I do it all the time too, though, casually.
i'm not totally sure, but if they found out they could probably prosecute because you're distributing it for free whether the person decides to keep it or not