A few of the possibilities so far:

• Community. A good word for the readers and participants on some platforms, but not necessarily on others. Howard Weaver says, “Community implies a kind of unanimity that I don’t think you can assume from readers of news. … If we define that word broadly enough to encompass a group who shares only its interest in news (eg readers of a mainstream news site) it has become vague to the point of uselessness.”
• Users. It’s suitably nonspecific, but it seems a little cold. As Ryan puts it, “we’re talking about human beings consuming and sharing information, not people who downloaded a piece of software.” Plus, it can have vaguely negative connotations. (“I’m a user and a loser, so I don’t need no accuser…“)
• Readers. That is one thing that all of the people being described have in common, no matter how active their participation level. And “Readers” doesn’t necessarily imply passivity in people’s minds — we’ve had columns titled “Readers Write” and captions saying “Reader John Doe sent in this photo of …” for years. But if you want to help bring about an attitude shift, continuing to say “readers” isn’t going to push you in that direction.
• Participants. The problem with this, I think, is that even on a news platform where everyone is encouraged to engage in the process of newsgathering and reporting, there’s a good chance that the majority of people will still want to be passive consumers most of the time. And there’s nothing wrong with that. We all have only so many hours in the day, and we can’t be active participants in everything we’re exposed to.
• Members. It works on discussion boards, but on a news site, it might keep people away by implying a level of exclusivity.
• Something site-specific. Dan Pacheco cites people at Bakotopia.com referring to themselves as “Baktopians.” DailyKos has Kossacks, Free Republic has Freepers. But like “community” in a way, it seems like it would work better on sites where people have a strong degree of commonality.