I remember the good old days long before social networks such as Facebook or Twitter were created; we used to collaborate in communities through online forums. Forums existed in all topics and they provided platforms for people with common interests to communicate freely outside the inflexible frame of the corporate website. You might see forums integrated with company websites to cover specific areas such as customer support or member discussion to allow free feedback from community members or product users for that matter.
This has changed a bit with the introduction of open social networks such as Facebook. People discovered more freedom with more features available in such platforms, and companies started to follow them there as well.