- Cross promotion
- platform leverage
- historical performance of similar games
- and all of this operating in a market segment (mobile gaming) that is exploding not contracting.
I don't think Zynga gains any long-term competitive advantage from this. Most people don't play games because they know the company that produces them, they play them because they are a fun novelty. Games are necessarily one-off successes at the mobile/social level, because there is not really a storyline or steep learning curve, so I believe that a company that produces one successful game is no more likely to produce another than a company with no previous successes, assuming equivalent technical know-how.
This reminds me a lot of when Mark Cuban sold Broadcast.com to Yahoo. Yahoo execs overreacted to the potential of the technology that Broadcast had developed, and were drastically overpaying out of fear of missing out. Not a great position to make acquisitions from.