Silverback makes it easy, quick and cheap for everyone to perform guerilla usability tests with no setup and no expense, using hardware already in your Mac.
Loop11 is a web-based user-experience testing tool, allowing companies to conduct online, unmoderated user testing on any kind of digital interface. Loop11 is not a survey or web analytics tool, but a user experience tool… helping you to understand user behaviour.
ImageAlpha is a GUI for pngnq and pngquant. It allows you to easily generate paletted PNG images with full alpha channel and test how it will look against different backgrounds.
Contrast-A allows users to interact with a 3-dimensional RGB color space, experiment with color combinations, check the contrast according to both WCAG 2.0 and 1.0 and see the results for different types of color deficiency.
SiteScan is a Google Analytics Diagnostic tool designed to provide you with a complete audit of your Google Analytics setup. SiteScan is a free way to ensure that your Google Analytics is configured properly on your website.
Firefinder is an extension to Firebug (in Firefox) and offers the functionality to, in a quick way, find HTML elements matching chosen CSS selector(s) or XPath expression. It allows you to instantly test your CSS selectors in the page while seeing the content at the same time, and matching elements will be highlighted.
Modernizr doesn't actually magically enable CSS3 properties for browsers that don't support them. It just tells the page whether that feature is supported on the browser the visitor is using or not.