We'd need to know acquisition costs and lifetime value (difficult to project with such a new product and with Google and Facebook coming up with potential competitors that might cause users to churn). The idea of looking at quarterly P&L and determining if a business is legit or not doesn't really make sense. Are they profitably buying growth (if acquisition costs are lower than LTV, you're buying future profits that don't show up on that quarterly statement) or just burning money? We'd also want to understand if there's any value to subsidizing things. Perhaps they're able to fine tune and improve based on what users are doing and that's helping them build a moat - or maybe there's no value there.