The soft stuff matters.
The silly games, the off-topic discussions, the gossiping, the humorous shared stories, the obscure references to in-jokes, and the petty conflicts between different personalities all play an important role in helping members feel part of a community.
If members feel a part of a community, they're more likely to do the things you want them to do. They're more likely to share information, support one another, help one another, give great feedback, and become more loyal to the organization that brought them together etc…
These visible benefits of a community is the tip of a very large iceberg. Immediately beneath the surface is the sense of the community. Beneath this are all the things that help make that sense of community possible.
If you take the soft stuff away the community sinks. It becomes a boring, tedious, information-sharing task to squeeze in when you've finished your important work (this rarely happens). It's not uncommon to organize outlandish team-building exercises as a short-cut to building a sense of community.
If you don't allow the soft stuff to happen, the community doesn't float in the first place. The goal isn't to prevent the soft stuff, but to proactively cultivate it. Underpinning all these soft elements is a deep layer of psychology.
We want to feel connected to one another. We want to enjoy the time we spend online. We want to interact in environments which are fun. We want to share our emotional states with those that feel the same and can understand us. We want to use gossip to enforce community values and acceptable behaviour upon the group.
Sure, the exact nature and the balance of soft activities changes by community. But the basic principles remain the same. A community of parents might enjoy word association games, gossip about celebrities, share parental advice, and share fun/silly pictures of their kids. A community of lawyers might share stories of problematic clients, exchange legal advice, arrange meetups, and argue about precise interpretations of law or ethics.
Notice, in both of the above examples, the desired result (sharing advice) is just one of the many things these communities do. The task for community professionals is to make our communities the fun, supportive, and mutually understanding places where we want to spend our spare time. Don't drain communities of their fun edges and quirky passions – introduce and encourage these things.
p.s. If you're interested in the psychology of communities. Attend the 2014 Virtual Community Summit in London on Feb 20 – 21. This is the first event dedicated to exploring and mastering the psychology behind successful communities.