Twitter (NYSE: TWTR) stocks dropped Wednesday after Facebook (NASDAQ: FB) announced it will launch an alternative to MoPub, the platforms mobile advertising distribution network, according to DC Inno. The stocks fropped 1.6 percent to $46.94 while Facebook stock rose 0.8 percent to $80.24. Twitter acquired MoPub two years ago and since has allowed its users to bid on advertising spots that reach a huge mobile audience, DC Inno reported. Facebook will announce these plans further at the F8 conference later this month. DC Inno commenter Brian Valdana said: “Twitter’s problem is largely comparable to that of Google’s and other mobile ad platforms that have either forgotten how to innovate or simply don’t care to any longer. You really can’t address mobile ad innovation today without talking about Facebook, Airpush, and a number of other young, up and comers that, while not household names yet, are all doing game changing stuff. That’s just not Twitter today. They’re not moving the needle on mobile advertising the way others are”