...Just googling 'live concert streaming' doesn't point me to streetjelly but rather the other sites I pointed out.
Gotta ask if you want to broaden your audience, wouldn't you want the site where you will perform to be somewhat known or obvious?...
As I found out about Streetjelly, I searched for others and two that I found were YouNow,
http://www.younow.com/, and StageIt,
http://www.stageit.com/ (of course there are a lot of others). StageIt seems more pro oriented and YouNow looks too big! I have also found that google+ has tons of "open mic" or live shows going on -- so there are no lack for alternatives. (There is also Second Life!)
StreetJelly seems likes the right mix of easy, accepting and small enough to have a showtime all to yourself. With YouNow, you might be sharing time with 1,000 other folks!
SJ won't be for everyone -- but what is?