Ikea is trialling an online second-hand marketplace where customers can buy and sell used tables, couches and other products made by the Swedish furniture giant. Ikea Preowned launched on Monday, initially only in Madrid and Oslo, as part of a test phase set to run until the end of the year, Ikea chief executive Jesper Brodin was quoted as saying in the Financial Times. If the trial proves successful, Ikea Preowned will be introduced globally, the company says. This expansion would put Ikea in direct competition with online platforms like Ebay or Craigslist, where second-hand Ikea products can…