Wall Street hasn’t been one of Facebook’s (NASDAQ: FB ), biggest fans—particularly when it comes to its inability to monetize mobile users, but that might be changing. Investors who stuck with the company are seeing the rewards in part because of improving mobile metrics. Facebook is finally proving to investors that unlike recent tech IPOs Zynga (NASDAQ: ZNGA ) or Groupon (NASDAQ: GRPN ), it’s an investable company. That doesn’t mean there aren’t still headwinds. According to the Daily Ticker , Facebook admitted that its 1 billion users are spending more of their time on competing services such as Instagram (which Facebook now owns), Tumblr, and Snapchat. But Facebook seems to have learned a lesson from Google (NASDAQ: GOOG ). CNBC’s Jim Cramer said, "After initially struggling Facebook has now mastered mobile and I think the company has a bright future." Cramer also referred to statistics reported by Facebook, ...