Coding: Sublime Text is an excellent cross-platform editor for code, html and etc.
Github: Github feed creates an RSS feed from commits to a Github repository.
HTML5: Request a users location with the HTML5 Geolocation API.
Instagram: Printstagram is a great service for making albums, prints and posters from your Instagram photos.
iOS: An introduction to the UITableViewController.
JSON: JSONLint is an online JSON validator.
Productivity: Vitamin-R is a very unique approach to time/project management.
Psychology: 13 tips for dealing with a really lousy day.
RSS: Feeder allows you to create, edit and publish RSS and podcast feeds.
TextMate: Essential shortcuts, tips and techniques.
WordPress: Extending the core functionality of WordPress.