popped up in the news headlines this week, I felt a jolt of nostalgia. I thought back to those long-ago days of 2005, when Rupert Murdoch and

News Corp.

(NWS) - Get Report

shelled out a half-billion dollars to buy the site that helped set off the social-networking craze. Back then, to be familiar with MySpace (or, even better, to have your own page there) was a sign of pop-culture savvy. It showed you knew what was cool.

Fast-forward four years. In the past week, MySpace announced that it's laying off 30% of its U.S. workforce, followed by two-thirds of its international staff. I realize it's been a long time since anyone referred me to their MySpace page.

Instead, all the buzz lately has been for


. It got a major boost this spring, when an "Oprah" episode centered on Oprah Winfrey's debut "tweet," messages sent through the service. More recently, it's been credited with fostering freedom of speech, as real-time reports on political protests filtered out from Iran.

But -- dare I say it? -- Twitter hasn't created a great new product or tapped into a huge un-met need. It seems to be coasting largely on hype. Which leads me to wonder: Could Twitter be the MySpace of 2009?

As companies of every size search for the secret to good buzz, consider the fate of social-networking sites a cautionary tale. If you're looking to grow your business, hype doesn't make for a solid foundation. Much as we'd like to see our brands adopted by trendsetters and enter the pop-culture landscape, popularity doesn't always translate into profits. And it can vanish in a flash: For the arbiters of hip, nothing's cooler than dismissing what was cool last year.

In many ways, social-networking sites live or die by their buzz. For a site to grow, it has to convince users that it's a place they want to be seen.

"The networks that succeed are the ones where your friends are," says Allen Stern, editor of


, which tracks developments in social networking, and founder of the business-card management service

Cloud Contacts

. "Media hype can be important, but what's more important is that you go where your contacts are. A site has to have that sticking power."

MySpace may have snagged News Corp.'s big bucks, but it wasn't sticky enough to fend off what became its biggest competitor:


. That's because Facebook reinvented the nature of the network: While MySpace encouraged a come-one, come-all attitude, encouraging users to connect with people they didn't know, Facebook offered exclusivity.

MySpace's multicolored, chaotic pages reflected its free-for-all spirit. In contrast, Facebook offered a neatly organized format where information would only be shared with approved users. That suddenly started to look a lot more appealing than MySpace. After all, what's cooler: a party open to whoever shows up, or one with a guest list?

"Facebook is like AOL was when the Internet first started taking off," Stern says of America Online, which is owned by

Time Warner


. "They keep everything tightly controlled."

Facebook's numbers are impressive. The company says it has 200 million active users, about half of whom log on to the site each day. (Whether that's translating into more profits is hard to answer, since it's a privately held company.) The fastest growing demographic is those 35 years and older. And that could be Facebook's ultimate downfall. As it attracts more users, it loses its cache. Once Grandma's on Facebook, how cool can it be?

Instead, the buzz that boosted Facebook seems to have migrated to Twitter. But it's hard to look at the examples of MySpace and Facebook without wondering about Twitter's long-term future.

"Remember how you would get a new game at Christmas, play with it every day for a few weeks, and then forget about it?" Stern says. "Twitter is a fine tool, but I think we'll see less usage of it in 18 months or so. People don't genuinely care what others are doing every minute. It's overhyped."

On the surface, MySpace, Facebook and Twitter couldn't look more different. But all three share one trait: They enable users to share information. The basic components of what's being shared -- gossip, birth announcements, photos, insults -- are nothing new.

Sure, they've made communication more immediate and wide-ranging. But none are creating products that improve lives in any measurable way. None are offering services that consumers are willing to pay for.

Buzz may help build a business, but solid relationships are what keep it going. Give your customers something they really need, and they'll remain long after the crowds have moved along to the next hot thing.

Elizabeth Blackwell is a freelance writer based in Chicago. She is the author of Frommer's Chicago guidebook, and writes for the Wall Street Journal, Chicago, and other national magazines.