I've been doing it for about 18 months in the Pro Tools area. (So,
technically, I'm on the list but I'm not doing it with Linux.)
I've found that (for me) it works best when someone has written a song
and is looking for other musicians to spice it up, just like being a hired
hand in a studio situation. I have a number of songs I've done with a
drummer in New York that I've never met. I also worked a bit with a musician
in Europe (The Netherlands) for a while. It's been an immensely rewarding
thing to do.
It has, again in my case, been much harder to try to collaborate like a
band does, where everyone is throwing ideas around and you all come up with
a good way to approach a song. Over the Internet is much slower, and you
cannot read how people feel about things very well through a few emails. For
these reasons, I find it's best to have a good idea what I want people to
do, or what they want me to do.
In the Pro Tools case we share the session files as we all have high
speed access and I have an ftp server. It is impossible to do this through
email. The track files get hung up in mail servers as they are too large.