For Twitter and Facebook, the two principal combatants in the world of social media, e-commerce is emerging as the newest battleground. One would think that Amazon's June unveiling of it's Fire phone should be pushing the transition even faster.
Twitter announced on Thursday that it had agreed to acquire CardSpring, a mobile payments infrastructure company that allows merchants to offer deals to consumers that can be loaded onto to their credit cards. When the card is used to pay at the store, the coupon is automatically applied.…
