Hacker News on 21 January 2015

• Hands-On with Microsoft's New Holographic Goggles
• A Designer's War on Misleading Parking Signs
• A Comprehensive Guide to Building a Scalable Web App on AWS
• What is the best hard drive?
• The Next Chapter – moot retires from 4chan
• Show HN: Hacker News' “most unique support email of 2014”
• An Intuitive Guide to Linear Algebra
• Emacs Is My New Window Manager
• How the 'John Oliver Effect' Is Having a Real-Life Impact
• An experimental real world adblock