re: #1 - Pinterest has dramatically more users and potential users. Will it be able to monetize them as well as GitHub? Hard to say without knowing the details.

re: #1 - Pinterest has dramatically more users and potential users. Will it be able to monetize them as well as GitHub? Hard to say without knowing the details. The other factor is hype. Pinterest is the next hot social company and their comps are Facebook, Twitter, LinkedIn, and Instagram. Easy to let your imagination go wild if you're an investor. re: #2 - they would raise money to a) grow faster, b) acquire companies, and/or c) provide shareholder liquidity. b & c are self explanatory, so let's focus on a): The wad of cash lets them hire faster. Let's say they have 70 employees today and they want to grow to 200 by year end (for enterprise support, for example). Hard to triple your salary expense that quickly if you're operating off cash flows. GitHub have a network-effect business, so why not lock-in every company on the planet as quickly as possible? It'll lead to a much, much greater profits in the long-run. It's only worth the dilution if you expect your equity to be worth more than 1/(1 - n) [See PG's essay: http://paulgraham.com/equity.html http://paulgraham.com/equity.html]