Six-second postcard the next big thing? IT'S the modern-day postcard - on steroids. With the declining popularity of the traditional postcard, travellers are looking for new more engaging ways to share their stories. Twitter app the Vine lets travellers capture and share short looping videos in what it calls the "Six second postcard." It's like .gifs, reborn, giving you a glimpse of places and people around the world. The app, currently available for free on the iPhone and iPod touch, is pretty inventive - and a bit of a spin out. It has been called: "What would happen if Instagram and YouTube had a love child." It's had a bit of time to be trialled over the last couple of months, so is it the evolution of postcards, or just another fad? Will it change how travellers share stories? Only time will tell, but it is starting to get some traction on Twitter already. The Tribeca Film Festival, which kicks off on April 17 in New York City, has launched a new competition called #6SECFILMS using Vine, and a growing group of Tweeters are beginning to embrace it. When announcing the app Twitter said it hoped the the brevity of the videos will inspire creativity. Its description reads: "Vine is the best way to see and share life in motion. Create short, beautiful, looping videos in a simple and fun way for your friends and family to see. See more of the vines here. Here are some examples: This Vine is from @Daisann_McLane: On the South China Sea in Hong Kong This vine is from @BrowsingRome: It's lunch time - Buon Appetito! This Vine is from @Foodieintl: New York dawn