Adding Pinterest.

Contributor: Tracy Chou, software engineer at Pinterest, @triketora
Source: internal headcount
Adding Dropbox.

Contributor: Amy Nguyen, @amyngyn
Source: Dropbox about page

https://twitter.com/amyngyn/status/389174564053209088
.@Dropbox has 9/143 women engineers based on their /about page.
Adding Medium.

Contributor: Don Neufeld, CTO at Medium, @dnf
Source: internal headcount

https://medium.com/grace-hopper-2013/cb997a57252#d4d8-afdaba64a8e7
Medium is currently 5/21, so 24%. Our 2013 Intern program was 3/8
Adding Rent the Runway.

Contributor: Camille Fournier, VP Architecture at Rent the Runway,
    @skamille
Source: internal headcount

https://medium.com/grace-hopper-2013/cb997a57252#d4d8-b3d509275bf9
Rent the Runway is 7 out of 32 if you just count dev + ops, 10 out of
37 if you count QA, 11 out of 39 if you count all the people I manage.
Adding Reddit.

Contributor: Ellen Pao, biz dev and strategic partnerships at
    Reddit, @ekp
Source: internal headcount