I am a pretty active observer of rust community as the language abilities and paradigms excite and suit me. Therefore I do see steveklabnik as well as several others frequent these avenues. In all my time reading Reddit/HN/etc. I've never seen steve or the others "advocate"; they're doing exactly what that description states which is explain and clarify. The tech community brings up rust as a discussion topic and they spend their own time (possibly some of Mozilla's) to make sure that the community understands the organization (not just Mozilla), drive, and tech behind rust.