You can now try out games via your Facebook news feed.FacebookFacebook is allowing people to try demos of mobile games via Playable Ads appearing in news feeds from Thursday. You'll be able to try sections of games without downloading them, the company says in an advertising-focused announcement. This approach has already proven successful, with Angry Birds developer Rovio noting, after a test run, a 40 percent lower cost per paying user and a 70 percent lift in day seven return on ad spending. "The explosive growth of the mobile app ecosystem poses a real challenge for today's game developers," said Rich Kelly, Facebook's vice president of global gaming. "It's no longer enough to build a great game; app developers must strategically market their games to capture the attention and loyalty of their most valuable players." In July, Facebook adjusted its policy on targeted ads by requiring advertisers to tell people if they're seeing messages because of info supplied by a data broker. The company also brought augmented reality (AR) to its ads by letting you "try on" clothes and makeup before you buy. CNET Magazine: Check out a sample of the stories in CNET's newsstand edition. Cambridge Analytica: Everything you need to know about Facebook's data mining scandal.