In regard to your screenshot without blurring out usernames- I’m not sure of the ethical concern at hand here. It’s undoubtedly safer and probably better to just black out the names. However, choosing a username already gives the commenter the option for an alias and consequently anonymity. If a commenter on a fan site elects to display their own name for the world to see, in a way they’re releasing their own privacy. Who knows what purpose someone might utilize information for on the internet? I’m not sure of the exact ethnomusicological protocol in this instance, but I suppose it could go either way ethically depending on how particular someone is.
I suppose consent isn’t so much an issue in the Miller article considering she asked for feedback from the GTA fans. However, sampling is definitely something to take into consideration here. On one hand, she’ll get the most enthusiastic and probably relevant responses from players who care enough to even know where to find these websites, let alone, take the time to follow them and post feedback. On the other hand, this is a very limited audience she’s drawing from in terms of involvement with the game. It being the internet, these subjects could potentially come from far and wide. However, it’s also important to take into consideration those who play GTA in the first place. For someone to have access to the game, he or she is likely of a certain socioeconomic class to be able to afford the system and game, and of a certain social group to hold an interest in participating.