Why Google Buzz will be a hit

Editor's note: Pete Cashmore is founder and CEO of Mashable, a popular blog about social media. He is writing a weekly column about social networking and tech for CNN.com.

(CNN) -- Google Buzz, Google's new social networking service announced this week, isn't particularly original.

Just like Facebook and Twitter, it lets you share links, updates and media with friends. Even so, it'll probably be a moderate success.

Google Buzz is perhaps the most generic "social sharing" service launched to date. Users can enable the service in their Gmail accounts to share status updates, photos, videos and more with the group of people they e-mail most often.

Friends can also comment on these updates or "like" them to express approval.

There isn't a great deal of innovation here; early adopters will remember FriendFeed, an identical service acquired by Facebook last year.

While FriendFeed built a strong technology platform with an advanced search engine, it failed to achieve significant mainstream success. The site's features are instead being integrated into Facebook, where FriendFeed's talented engineers and Facebook's massive reach (more than 400 million users at last count) combine for maximum effect.

Good technology has value, but leading social networks require "network effects." Facebook is infinitely more valuable because all your friends are on it.

Facebook has leveraged this "critical mass" of users to stay ahead of new rivals, too. Why visit Twitter, you may ask, when Facebook has continually extended its feature set to keep up with its less popular competitor?

The story of social networks is in fact a story about network effects: How can a service reach a point at which there are enough users and content to be useful?

YouTube achieved this trick by providing embedded videos for MySpace and blogs, siphoning off members along the way. MySpace eventually chose to block YouTube links and build a rival video service, but the move came much too late to halt YouTube's rise.

Photobucket, meanwhile, became one of the world's largest photo sites by providing photo hosting to MySpace users; MySpace parent Fox Interactive Media (now News Corp. Digital Media) acquired the service in 2007.

There are arguably better video sites than YouTube and better photo hosts than Photobucket, but network effects tend to trump technical prowess in the social networking realm.

Google Buzz certainly isn't groundbreaking, but it will achieve critical mass virtually overnight. Thanks to integration with Gmail, the new tool is in the eye-line of the millions of users who obsessively check their inboxes for new mail. ComScore pegged Gmail at 176.5 million unique visitors in December.

What's more, Google Buzz uses data about those you frequently e-mail to automatically build a social network for you. Gone are the challenges of critical mass faced by virtually every new social networking service. In Google Buzz, your address book is your network.

Two forces are at work here, then: the immediate utility of a social service pre-populated with people you know, combined with the habitual behaviors associated with checking your email throughout the day.

A stream of fresh content from people you care about, served up on a site you visit every day, may prove to be an irresistible attraction -- although perhaps not a novel one.