When browsing a web page, there are usually many 3rd party scripts (analytics apps, ad networks, widgets, font services, etc.) that add a cookie to our computers and "can" track us.
With the increasing importance of "privacy" on the web, Collusion, an experimental add-on by Mozilla, aims to increase user awareness and can help us see + analyze "who is tracking us".
Once installed, it sits in the add-on bar and, when clicked, displays the services that are tracking you. The great part is, it creates the tracking relations for all the web pages browsed which is so good to better understand "what type of personal info is being given away".
As the add-on gets developed, it'll also enable us to decide when, how and if we want to be tracked (you'll remember that there are more extraordinary actions for that).
Page Speed, the popular Firebug/Chrome add-on -by Google- for evaluating the performance of web pages now gets an online version.
It offers a very similar functionality with the Firebug version, analyzes the page performance and comes with suggestions that are categorized in priorities to improve it.
This free service also has a new feature: "suggestions for the mobile version of a web page" which are tuned for the unique characteristics of mobile devices.
foxGuide is a firefox extension that can display both horizontal and vertical guides on web pages.
The guides can be moved or removed just like the ones in Photoshop. Also, you can set the transparency and color of them for a perfect fit.
The extension has a memory which remembers the guides created per website. Even if the browser is closed or the URL is changed, the guide for that web page is stored.
foxGuide also works well for pages that have huge width/heights (supports up to 10,000px).
ColorZilla is an impressive Firefox plugin that assists web developers and graphic designers with color related tasks.
A built-in eyedopper can get the color of any pixel and a color-picker helps playing with colors instantly. Picked colors can be added to the plugin's palette viewer/editor.
Also, generated or sampled colors can be auto-copied in CSS RGB, Hex and other formats which is handy to paste them into image editing apps.
A great feature is the ability to generate the color palette of any web page automatically and seeing where they are exactly used.
Beside these color-based functions, it can also measure between any to points
BrowserLab, a web-based service by Adobe, enables you to test websites on multiple browsers and OSs.
It is possible to create a custom browser set where the screenshots will be created only for those browsers (also helps speeding up the results).
Screenshots can be previewed in 2-up or onion-skin views which makes comparing multiple versions easier and x/y rulers can be used for sensitive measurements..
The service currently supports different Firefox, Safari and IE versions for Windows and Mac OS X. However, it is still in beta and new browsers are added within time.
BrowserLab is part of the Adobe CS Live and free for 1 year if you sign-up before April 30, 2011.