According to Web 2.0 ideology, all sharing is good, by definition. Users will run to embrace any feature that increases their ability to share information with their community. Sharing. Community. It’s all so warm and fuzzy — what could be wrong? But Facebook discovered the hard way that there are limits to Web 2.0 sharing ideology.

Mark Zuckerberg, the creator of Facebook, has published an open letter apologizing for the feed features that overstepped Facebook users’ comfort level with sharing. He also announces new features that give users more control over their privacy (although not the ability to turn the feeds off entirely).

The Facebook privacy backlash should be a stark lesson for every Web 2.0 company and social/sharing/community ideological advocate. Yes, the web is making us more open, more networked, more social, more community-enabled. And this is all good.

But it’s a scary world out there. Especially after 9/11 and high-profile privacy incidents like AOL’s data release, we all feel vulnerable. There is a downside to openness and sharing that we need to manage. We need assurances that we will be safe (even if we’re really not). And we need control over our personal space.

The lesson for Web 2.0 social software developers is (duh) that the USERS ARE IN CONTROL. They feel ownership not only over their content, but over the platform as well. When you empower users with your software, it means that you can’t go changing it without the users’ consent. Facebook made the mistake of thinking that they were in control of the software. But they’re not — they’ve already ceded control to their users. And without the users, they have nothing.

When you live by 2.0 ideology, then you are bound by 2.0 ideology.