It's plausible if they simply subvert the servers. If you take World of Warcraft, say, the options are basically text chat and voice chat. (Sure, you can send m

It's plausible if they simply subvert the servers. If you take World of Warcraft, say, the options are basically text chat and voice chat. (Sure, you can send morse code or whatever, but that kind of sophistication generally assumes a more detailed communication has already taken place and applies everywhere -- "let the phone ring three times and then hang up", steganography, etc.) A better option for covert communication would be a more open platform such as Second Life, where you can upload custom content. But, frankly, there are so many options if you have any imagination... If what they're really worried about is recruiting and outreach then they at least only need to worry about reasonably popular alternatives.