The Wikimedia Foundation :)
We make sure the tech behind Wikipedia and sister projects is up and running smoothly. A rather high number-of-users/supporting-staff ratio. All the work we do is  public and open source (<a href="https://git.wikimedia.org/" >). You get to work with other paid staff from all around the world, as well as wonderful volunteers. We are about 200 people now, and have an office in San Francisco (although more than half the staff is remote).
Various positions listed at <a href="https://jobs.wikimedia.org" > :)
Both remote workers and people seeking H1B are welcome (Do check the particular job posting to confirm)
Ask HN: Who is hiring? (January 2014)