O2 has prioritized sponsorship as a key platform for keeping customers happy.The wireless services provider uses its long-running partnerships with The O2 Arena, Rugby Football Union and 19 O2 Academy music venues to access perks for its Priority customer loyalty program.And the strategy appears to be working: O2 has reduced contract churn from 1.8 percent to 0.9 percent over the last decade, a result the company credits in part to its marketing investments.“The Priority program has result...