As it's Friday, we're going to offer a tip and a treat today. Unless you've been fairly well hidden under a rock, you'll probably know that tickets for Take That went on sale earlier this week. Naturally, those lucky online businesses who sell the tickets have been ready and prepared for the onslaught of fans - or have they? In actual fact, it seems that all the big name ticket sites have failed to prepare for the demand and none of them had the vision to see the opportunity ahead. Users want immediacy and when a site is slow or…