Let's face it: Twitter is a virtual haven for self-promoters. Celebrities plug TV appearances, authors hawk books, journalists promote articles and—as a reward—everyone's followers respond with praise via the all-important retweet. It's a continues loop of adulatory backslapping .

But is this such a bad thing? In the July issue of Wired magazine (not yet available online), Evan Ratliff explores the nature of bragging on Twitter. He finds that a little vanity—though annoying—is a necessary evil. That's because social networks are fragile and rely on positive feedback loops to reinforce themselves. While snark and cynicism are the modi operandi of comment boards, social networks are different:

James Fowler, a political scientist at UC San Diego who studies social networks both online and off, has shown that positive networks built on cooperation and altruism tend to thrive, while negative ones tend to dissolve. "Apparently, evolution favors behaviors that cause us to disconnect from mean people," he says.

And why not? In a modern world that bombards us with reasons to feel bad about ourselves, maybe there's room for a little extra public celebration when things go well. Online, we're safe to note our achievements, our loves, our tiny daily triumphs in a bid for a little positive feedback. So go ahead and, as the marketing gurus say, tend the Brand of You. Just don't be me-first. Roll as many logs to others as you do back to yourself. Promote those deserving friends too humble to promote themselves and you'll be tending the entire social-network ecosystem.