Mr Jolstad and his co-founder Ilya Kruglenko - who first met each other in Moscow during the 1990s while selling second-hand Australian telephones to the Russians - initially created Magic Desktop to protect their own children from getting tangled up in an unpleasant web.

BBC: Magic Desktop browser

It was the first time they'd met each other's kids, who ranged in age from about 7 to 15.

WSJ: Why French Parents Are Superior by Pamela Druckerman

Barcelona and Chelsea met for the first time in 2000, but have since faced each other a dozen times in a series of increasingly acrimonious battles, highlighted by their notorious showdown at Stamford Bridge in 2009, when Barcelona advanced on Andres Iniesta's stoppage time equalizer, which came after Chelsea had been denied three apparent penalty kicks.

WSJ: It's a Very Cross-Border Rivalry