ringtones?
Just in case this never occurred to you: When I tested it out, banged in a message and then got to the recording part, I was kind of stumped as to what to record so I just started rambling. That's weird if someone listened to that, my sending my own voice. And were I to turn on some Led Zeppelin track and record that, either making a short recording of my voice or a lousy 15 second recording of the Rain Songin mono, that would be an odd recording that would stand out on its own.
So I'm thinking, now what audio might someone casually and inconspicuously send from one phone to another that wouldn't look to bizarre were someone to see or intercept the email -- sending a buddy a ringtone maybe. And on Android those tones are oggs I believe and maybe stegdroid could loop and stitch them however many times as needed to squeeze in a message and then cut the looping off, as phones do when they ring. The program selects a ringtone at random or by choice, and stegs in the message.
?