Open Web Analytics (OWA) is open source web analytics software that you can use to track and analyze how people use your websites and applications. OWA is licensed under GPL and provides website owners and developers with easy ways to add web analytics to their sites using simple Javascript, PHP, or REST based APIs. OWA also comes with built-in support for tracking websites made with popular content management frameworks such as WordPress and MediaWiki.
JpGraph is an Object-Oriented Graph creating library for PHP >= 5.1 The library is completely written in PHP and ready to be used in any PHP scripts (both CGI/APXS/CLI versions of PHP are supported).
QtWeb is a fast, lightweight and portable browser with some unique UI and privacy features. QtWeb is an open source project based on Nokia's Qt framework (former Trolltech) and Apple's WebKit rendering engine (the same as being used in Apple Safari and Google Chrome).
Arora is a lightweight cross-platform web browser. It's free (as in free speech and free beer). Arora runs on Linux, embedded Linux, FreeBSD, Mac OS X, Windows, Haiku, and any other platforms supported by the Qt toolkit.
Object Oriented CSS
JS Bin is a tool for experimenting with web languages. In particular HTML, CSS and JavaScript, but JS Bin also supports other languages too (like Markdown, Jade and Sass).
JS Bin is ultimately a code sharing site.
Python snippets with REST apis
sonicsquirrel.net is a platform dedicated to netlabels and netaudio.
All music you find here is released under open licenses (mainly Creative Commons).
(X)HTML5 Validator
The mobiReady testing tool evaluates mobile-readiness using industry best practices & standards.
A place to put your favorite song of the moment & hear great music, handpicked every day by friends.
Pipes is a powerful composition tool to aggregate, manipulate, and mashup content from around the web.
Inspired by Yahoo's Pipes, DERI Pipes is an engine and graphical environment for general Web Data transformations and Mashup.
Landing page optimization for your mocks and wireframes.
Fivesecondtest helps you fine tune your landing pages and calls
to action by analyzing the most prominent elements of your design.
Pngcrush is an optimizer for PNG (Portable Network Graphics) files. It can be run from a commandline in an MSDOS window, or from a UNIX or LINUX commandline.
Its main purpose is to reduce the size of the PNG IDAT datastream by trying various compression levels an PNG filter methods.
Digital Publishing Platform
Color palette generation tool
Etherpad is an Open Source online editor providing collaborative editing in really real-time powered by Node.js
Search and Analyze the Social Web.
Web Based Ajax Development Tool