Social media
Even if you are not represented by a union, federal law gives you the right to band together with coworkers to improve your lives at work - including joining together in cyberspace, such as on Facebook.
Using social media can be a form of "protected concerted" activity. You have the right to address work-related issues and share information about pay, benefits, and working conditions with coworkers on Facebook, YouTube, and other social media. But just individually griping about some aspect of work is not "concerted activity": what you say must have some relation to group action, or seek to initiate, induce, or prepare for group action, or bring a group complaint to the attention of management.