Facebook app companies can be very different (team, expertise, products), so comparing valuation just based on number of monthly active users is pretty inaccura

Facebook app companies can be very different (team, expertise, products), so comparing valuation just based on number of monthly active users is pretty inaccurate. Google's acquisition of Slide is an example where the valuation (nearly $200M) was based on the founder, the team and their experience -- not their MAU.