Some things can't be summed up in 140 characters. Twitter Inc's announcement that Dick Costolo would exit as CEO on July 1 was long on plaudits but offered few clues on how the company will tackle its biggest problem: user growth.
Mobile payments are having a heyday. Apple Pay has been splashed across the news and 20-somethings are paying for taxis with their smartphones. Yet one stalwart risks being left out of the conversation: PayPal.