I just accepted an invitation from Jagex to become a RuneScape player moderator. This means I can now send priority abuse reports and mute players for serious rule violations. In addition to having a silver crown next to my name in chat, I can also post on the official forums as a free user. Besides these things, player moderators don't get any special perks.
For those concerned about player moderators abusing their power, there are guidelines on when we can mute people. Before anyone asks, I can't disclose much else as the player moderator manual is confidential. That said, you needn't worry about being muted as long as you follow the rules. :-)
Currently playing: RuneScape