Culture of Collaboration
"Rather than shooing employees back into their cubicles and banishing social media, try gathering everyone around the water cooler for a discussion about what is trending on Twitter."
While encouraging collaboration is important and employees should feel like they can socialize with each other you really can't force it. A manager calling a meeting at the water cooler with a list of "hot topics" is just another meeting. If they walk into a conversation, join the conversation for a couple minutes then walk away they will do more to foster the feeling that these interactions are good than rounding everyone up for a "talk". Building that environment takes time and an awareness of how interactions are represented.