Cola rivals Coke and Pepsi gave their long-standing feud a rest last week after a user-provoked experiment on Twitter prompted the two pop makers to trade friendly greetings on the popular social networking service.

Coca-Cola responded first to a clever user's message suggesting that the two make nice on Twitter, offering "A gracious (yet competitive) hello" to Pepsi. In return, Pepsi extended a Twitter-style olive branch of sorts to its competitor: "Can rivals and tweeps coexist? We're willing to find out. :)" Tweeps, for those unversed in the lingo, is a cutesy term for Twitter users.

The whole episode began with the single Twitter message sent by a digital media consultant from a web marketing firm called Amnesia Razorfish based in Sydney, Australia, but quickly grew as other users got in on the fun and repeated (or "retweeted") the message to their own friends and followers across the social network.

Within three hours of the original message being sent, Coke had fired off its friendly response and even decided to add Pepsi to its Twitter network. Pepsi took a bit longer to respond but wasn't far behind in returning the virtual handshake.

Considering both companies' long-standing commitment to the whole cola-war marketing scheme, such a quick decision to take part in the digital truce may come as a bit of a surprise. But what's probably more illuminating about the viral affair is that it shows two companies with deeply established brands adapting their marketing strategies to the world of social networking.