Social media promises to connect people across distances big and small, no matter where people are physically located. Social networks do provide a platform for that, but only if you become a member of the network that connects the people you want to connect with. If you use Facebook, while a friend uses Twitter, that’s a no-go unless you both use the opposing platform or look at things without interacting with them. It’s worse when it comes to interest groups that operate primarily on a particular social network. Without using the platform, it’s impossible to keep up with and to participate with the group. Many social platforms aren’t as open as they pretend to be, and limit how much you can see (if anything at all) and stop you from interacting until you sign up.

Physical communities have been using online platforms to connect for a long time. Technologies such as email have provided open ways for anyone to be involved before the rise of social networks. The move to social media is logical because dedicated social networks provide more features and more powerful community building platforms. Unfortunately, as social networks have developed into their own fairly closed ecosystems, communities have been closed off from people who choose not to be part of those social networks. Some communities rely on social media so much that their social media presence is the only place they exist online. Membership rosters, events, and even organization documents might be inside a closed ecosystem.

Although social networks such as Facebook like to remind us that “Your memories are important to us,” we don’t know how committed they actually are to that idea. On Facebook, communities have disappeared due to disgruntled users or political groups abusing the “Report Abuse” button or for comments that weren’t their fault. Facebook also makes changes to their news feed algorithm that make posts from fan pages and groups appear more or less often based on industry secrets. Just in the past month, Facebook announced they would roll out a news feed change that would change what shows up in news feeds, with a focus on friends more than groups and pages.

Intentionally or not, this has some interesting effects. It gives the social network site the ability to control how real-world communities interact and what they see of each other by changing how often their posts appear—which is why a requirement of neutrality for online services is so important. It also forces more people to join the network to participate in even local communities, or to choose to be excluded if they don’t want to use the social network for any reason. Worse, it walls off information from the rest of the online ecosystem.

The effect of walling off information extends beyond the network itself. News networks, local organizations, political figures, and all manner of other people and things encourage people to talk to them via social media. This can mean that it’s difficult to impossible to be heard by your local community, despite physically existing as part of it, if you’re a member of the wrong social networks. Or, maybe more interestingly, the section of your local community you can experience online isn’t one that matches your values. Demographics differ a bit between different social networks.

Social media sites are generally free to run their service as they want to because other than outcry from their users and advertisers, there aren’t many hard rules they need to follow. We’re seeing social media giants—some of the most successful services online—break away from the principles of openness and choice that the Internet should provide. While this is a fairly recent issue, it only stands to get worse as services close themselves off more and wall off more information from the rest of the Internet. Should they develop political motives, go offline, or change their target audience, there is a lot of content and a lot of communities that could disappear from the Internet.