Data analytics firms that analyze vast amounts of public social media are a tool for law enforcement. But there are signs that Twitter, Facebook and others are shutting off access to that data.

Sure, the data that’s being scanned is public, but it’s the fact that the police are using it to track protesters that is making the sites start to limit access.

“There’s a difference between posting something online, and thinking that that information is going to end up in a huge database that the police are going to be able to search through at any time for any reason,” Ozer says.

In other words, due to the very nature of social media and the fact that we are all related to each other through varying degrees of separation, police could retroactively use this data to try to build a case against any protester in the future they felt was a threat to the current administration.

Source: Police Searches Of Social Media Face Privacy Pushback : All Tech Considered : NPR