I think sharing is mutually beneficial and doesn't require reciprocation.

I hope you're right. Because the economist sand pinstripe guys are telling us that everything you do for and with others is reciprocal. You just help someone move, because you might need his help in the future; you just give money to a beggar, to buy yourself a letter of indulgence; yaddah, yaddah, yaddah…

I think business people don't understand that sharing can be something more than just closing a deal, because it's hard for them to understand the concept of non-zero-sum-game. It's had to understand for everyone: There will never be more cake, just because you share it with others. But having a party and eating the cake together might make it so much more enjoyable that one piece of cake is better than the whole cake eaten alone.