The best way to help bitcoin go mainstream is not to calculat the popularity. If the result is bad no one will invest in bitcoin anymorr. If the result is good big investors will not invest due to the already big market.
Popularity of bitcoins can be calculated by the adoption level. If the adoption level keeps on increasing day by day, than the bitcoin is gaining popularity, if a small grocery shops starts accepting bitcoins as a mode of payment than it is gaining popularity. If every single person is aware about the pros and cons of bitcoin than it is popular or else it is not.
Sure, but the difficulty comes in how to measure such adoption. As far as I am aware there isn't a database of all outlets accepting bitcoin that is updated regularly or for global wide businesses.