The spreading use of iPods and other personal music players, cell phones, and other earphone-bearing devices serve as another boundary; even with someone's eyes purposefully avoiding any approach, a simple "Excuse me?" can attract their attention -- but not if they are out of hearing as well. This would require someone to speak much louder, which is frowned upon in public, or even (gulp) tap the person on the shoulder -- a major invasion of personal space. We live in a world where we spend an increasing amount of time locked into our own private worlds, and demanding the privacy and security of that world. It is no surprise that this has extended to our physical homes and neighborhoods. The problem is that the problem is self-perpetuating: the less we share of ourselves or attempt to communicate with others, the...

This increases our need for security, so the gates get bigger and the neighborhoods more exclusive, creating more difference and distrust, and so on.
Creating a stronger sense of community is a tricky proposition. No one can be forced to enjoy someone else's company, and it would be quite plainly and horrendously wrong for any organization to attempt to compel someone's presence at a communal event. Yet these types of events are perhaps the only way to start correcting the underlying problem that causes gated communities to spring up. Neighborhoods and communities should invest time, energy, and money into greater social interconnectedness; when everyone is comfortable with everyone else, there won't be a need for gates or walls.