Twitter has invested an undisclosed sum in Boston-based proximity marketing specialist Swirl, hinting the social media platform could be looking at using Bluetooth Low Energy (BLE) beacons to push messages. The social media giant has invested alongside Hearst Ventures, Softbank Capital and others in an $18m series-C round, taking the total raised by Swirl so far to $32m.

Next: Visit the NFCW Expo to find new suppliers and solutions