Tracks

Tracks is an excellent web-based application that provides assistance in implementing David Allen's Getting Things Done methodology. This nifty utility was crafted using Ruby on Rails, which means it is a fully customizable application that comes with its own webserver (WEBrick). A remarkable feature of Tracks is that it can be run on your personal computer if you so wish.

This app is completely cross-platform and will run flawlessly on any platform that has Ruby installed, including Mac OS X, Linux, and Windows XP. As for requirements, Tracks necessitates Ruby, RubyGems, and a database. Nonetheless, that shouldn't be much of a bother as it offers tons of benefits.

Overall, Tracks is a powerful and versatile application that offers an excellent platform for implementing David Allen's GTD methodology. Its advanced features, ease of installation, and cross-platform compatibility make it a must-have for anyone looking to streamline their productivity by adopting GTD.