One of the questions we are asked the most about social media is “what’s the next big thing”? What’s the next big network? Where should companies be looking next? How can we get ahead of the curve and find the next Facebook, the next Instagram, etc.?

The answer may be a bit disappointing. Facebook seems likely to be the last of the mega-networks. It’s a rare and unique accomplishment to build a brand that talks to over a billion people on a regular basis, a rare and unique accomplishment to connect 44% of the Internet-enabled human race. What’s next isn’t likely to be another single major player at all. What’s next is more likely to be fragmentation. More and more companies see an opportunity to specialize in an aspect of social networking and excel at it, something that sets them apart from the monolithic Facebook/Twitter/Google+/LinkedIn oligarchy. After all, if a new market entrant offers no feature better than Facebook, chances are people will just stay with Facebook, since that’s where all your friends are already.

What kinds of features might compel someone to spend less time on Facebook? Here are three classes of social networks you should probably pay attention to. First are the chat apps. These apps are incredibly popular, especially in parts of the world where SMS text messaging is expensive and Internet access is cheap. Apps such as Tango (SHIFT client), WhatsApp (now a part of Facebook), Line, Kik, WeChat, Path, and others provide a friends circle without the “pollution” of commercial advertising that fills up Facebook news feeds. Serendipity and meeting new people is more difficult with these apps, but users make that tradeoff in exchange for being able to privately talk with their friends.

The second class of social networks are the rise of anonymous apps such as Whisper, Rumr, Secret, Confide, YikYak, etc. These apps are growing in popularity by leaps and bounds because they offer a promise of anonymity (though how anonymous they truly are remains to be seen), which in turn stimulates discussions that aren’t found in identified public social networks. It’s much easier to state something controversial when you believe that your identity is not at stake. In an era when your entire career can be ended by one tasteless tweet, anonymous apps have a great appeal.

The third class of social networks are the increasing dominance of media-first apps such as Instagram, Snapchat, Flickr, Minecraft, DeviantArt, etc. that have social aspects but are fundamentally about the creation of media. YouTube isn’t just a search engine, it’s also a social network (though technically part of Google+). Content creation online is nothing new, but in an era when everyone is struggling to find their voice, versatile content creation abilities is a defining factor.

These three classes of applications and social networks pose three very difficult problems for PR and marketing professionals. First, they’re incredibly difficult to monitor. The era of “full firehose” social media monitoring has numbered days as more and more conversations occur behind closed doors in private chat groups, or on platforms where identity is completely obscured. There will always be a place for public discussions and communities, but the trusted referrals and conversations will increasingly happen out of sight and out of monitoring tools’ reach. How much more powerful is a positive brand mention if no identity (and thus no social status) is tied to it?

Second, they’re incredibly difficult to participate in at scale. When consumers have conversations in invitation-only private spaces without brands, there’s no way to fight new fires or perform advance crisis communications. The first signs of a problem will be when larger groups of people begin taking public action together – long after a decision has been made behind closed doors. Brands will largely be excluded from participation at the lowest grassroots levels or intercepting problems before they brome crises.

Third and finally, these changes will demand much more of brands. Brands will need to become much more versatile at content creation just as a differentiator – the days of posting text status updates are growing shorter. Most importantly, with many of the trend-setting conversations happening behind closed doors, brands will need to focus much more on what their brand actually means and stands for, since the only people who will be able to defend the brand in a million private conversations will be its advocates and evangelists. Closed-door communities are largely immune to astroturfing and other popular (but dishonest) tricks.

None of these changes will happen overnight, or even in a couple of years. Facebook’s dominance isn’t likely to fade immediately, no matter how many times they change the newsfeed. These are large macro trends, not imminent changes, and brands will have a few years to make changes. That said, the top ways to future-proof your brand against these trends are to strengthen the brand with quality products, incredible service, and unique experiences that only your brand can deliver. Your brand’s future success hinges on your ability to get people talking about your brand without your participation. Build now for the day when your best fans and worst enemies will be largely invisible to you.