While the nations at Euro 2016 "have done battle on the pitch, an equally intense battle has been taking place off it between brands that want tournament exposure," according to Chadwick & Fenton of THE MEDIA ONLINE. Sponsors such as Coca-Cola, McDonald's and Carlsberg "spend multiple millions" to be associated with the Euros, but they have "also had to compete with a bunch of mischievous brands seeking to attach themselves in an unofficial capacity." Ambush marketing is an "established phenomenon, but social media has become the perfect new vehicle for it." UEFA regulations sometimes make it "tricky for official sponsors to respond quickly and effectively to events in the campaign," and these ambushers could "undermine the value of one of the hottest tickets in advertising" -- not to mention other major events. The official sponsors of Euro 2016 "are heavily active on social media, of course." Where once 30-second commercials on primetime TV dominated advertising, "the likes of Twitter and Facebook have become hugely important in recent years." But beyond this "closed circle," a world of brands use social media to "draw attention to themselves by ambushing their rivals." One of the stars of Euro 2016 is Iceland -- the British frozen food chain. When Iceland qualified for Euro 2016 as "the unfancied minnows," its supermarket namesake signed a deal to sponsor it. It has been "wreaking havoc ever since." Iceland’s 1-1 draw with Portugal on June 14 was "a good example." The retailer trolled Nandos, an int'l restaurant chain with a Portuguese theme, and goaded Portugal striker Cristiano Ronaldo "with the offer of chopped onions, to the delight of Twitter users." Betting company Paddy Power "is another ambusher that is savvy with social media and has been tweeting constantly during the tournament." It poses a "serious challenge for UEFA and the owners of other major sporting events" -- all of whom tend to use a "similar approach" (THE MEDIA ONLINE, 7/6).