If you worked in a cubicle farm you'd know. The cubicles were generally divided by low portable walls. There were different setups but generally you don't see people when you're seated but if you stand you can see your neighbors.

I think he means literally talking to someone on the other side of his cubicle wall.

For me it boils doen to, communication is key, talk to each other, exchange ideas.

I think it means taking to people outside your team, about your personal interest areas.