On old Route 66 just outside LA, there's a museum marking the spot where, in 1940, two brothers called Dick and Mac McDonald opened the world's first restaurant which made hamburgers on a production line – thereby spawning an entire, artery-clogging global fast-food industry.

Today, Los Angeles is in the early throes of another great culinary revolution which may, in due course, be regarded with a similar brand of lip-licking nostalgia as the one which produced Dick and Mac's golden arches. In recent months, this trend-setting metropolis has given birth to its first wave of Twitter Restaurants. These venues, which we shall, for want of a better word, call "Twitraunts", are in fact small trucks, fitted with rudimentary kitchens, which nip from street corner to street corner, like a traditional burger van. At the same time, they "tweet" their every move on the modish micro-blogging website, prompting vast flash-mobs of iPhone-toting customers to converge wherever they stop.

What makes them a success however, is the food. These vans don't sell old-fashioned junk. Instead, they employ top-notch chefs who produce ranges of high-end, inventive street cuisine which is among the most delicious and sought-after grub available anywhere in Southern California.

Most famous of the new Twitraunts is KogiBBQ, which sells Mexican-Korean "fusion" dishes such as spicy pork tacos and oriental quesadillas – and often boasts 45-minute queues at its serving hatch. Other prominent ones include ItsBentoBaby (Japanese "soul" food), FlyingPigTruck (Asian-French "fusion"), BarbiesQ (Hog Roast), and the self-explanatory BigGayIceCreamTruck. Together they have now become so prodigiously fashionable that several were recently included in LA Weekly's prestigious annual run-down of the city's top 50 places to eat, which is compiled by the newspaper's Pulitzer Prize-winning food critic Jonathan Gold.

Cynics, or Twitter refuseniks, have of course dubbed them a flash in the pan. But I wouldn't be so sure. In Dick and Mac's day, cheap meat came along, so LA created fast-food; then cars became ubiquitous, so it popularised drive-thrus. Now we have social networks, so LA has responded, in typically confident fashion, with Twitraunts, the latest milestone in a time-honoured tradition of culinary innovation.

Unfriend finds favour

Speaking of social networking, the Oxford American Dictionary made headlines this week by unveiling its "new word" of the year: "unfriend," a verb, meaning to dispense with an acquaintance via Facebook. It beat off competition from "teabagger," a term which supposedly refers to opponents of Obama, but previously appeared (in a different context, wholly unsuitable for a family newspaper) in Viz magazine's Profanisaurus of swear words.