500px is a popular photo sharing site that enables photographers sell prints of their work. They use Ruby on Rails, a free/open source web framework to build their platform. While they aren’t wholly committed to contributing to free/open source software (their Github profile page only shows code that makes working with 500px’s API easier), they do use free/open source software and they also develop a solid relationship with developers. On November 17, 2012, 500px hosted Pixel Hack 2012, a hackathon where the focus was on creating things that used open rich media APIs. It was a success and generated a positive image with developers.
They recently released more source code, for a plugin that integrates with Adobe Photoshop Lightroom. It already has 18 developers following the project.
500px understands that free/open source software plays a huge role in why a software engineer will apply for a job. Hosting hackathons and internal hackdays (similar to Google’s 20% where employees work on whatever interests them) and preferring to use free/open source software gives potential new hires the opportunity to see what the work environment is like. This gives 500px an edge over their competitors when hiring outstanding software engineers.