Pinterest is a unique platform catering to the shopping community. Very recently, PINS announced a cross-marketing facility for merchants. This should reduce friction for shop-owners as they use the same advertising campaign on multiple platforms. While the feature is presently only available in North America, it is expected that the service will be launched in Australia and Europe later in the year.
Pinterest is in its early life stage as a marketing and sales platform. Given this, estimates are probably on the lower end. In terms of valuation, valuation ratios should be closer to that of SNAP rather than FB or TWTR.
Provided Pinterest continues executing as it has done in the last few years, and provided it can monetize its user-base while expanding internationally as it has done recently, then Facebook might serve as an example of how the stock could fare.