in this thread, please post whichever addons/extensions you have found useful in your interwebs usage...
please link, and please post for which browser it is lol
what i find useful for Firefox:
1-ClickWeather for Firefox enables users to quickly view current weather conditions including regional Doppler radar maps (with severe weather alerts, when applicable) and/or international satellite maps and up to 5 days of forecast information within the browser and allows for instant access to detailed and customized weather content including hour-by-hour and 10-day forecasts and user-selectable video synopsis of weather conditions for the next 72 hours by On-Camera Meteorologists from The Weather Channel through clickable icons. All weather data is provided by weather.com.
AboutPlug is a simple extension adds menu item "About Plug-ins" to menu Help. When you select this item, page about:plugins is showed.
Adblock Plus allows you to regain control of the internet and view the web the way you want to. The add-on is supported by over forty filter subscriptions in dozens of languages which automatically configure it for purposes ranging from removing online advertising to blocking all known malware domains. Adblock Plus also allows you to customize your filters with the assistance of a variety of useful features, including a context option for images, a block tab for Flash and Java objects, and a list of blockable items to remove scripts and stylesheets.
All Glass For Firefox gives your Firefox a clean and fresh look by adding Aero Glass pretty much everywhere in the frame.
Better GMail 2 adds useful extra features to Gmail, like hierarchical labels, an unread message icon on your browser tab, file attachment icons, and more.
Compact Menu 2 replaces the original menubar into a single menu or icon.
Date Picker/Calendar for your statusbar and puts a quick popup allowing you to view a calendar or pick a date.
Dictionary Search looks up a user selected word in an online dictionary.
Download Statusbar allows you to view and manage downloads from a tidy statusbar - without the download window getting in the way of your web browsing.
Extension Manager Extended is an Addon Manager that views the id, date installed, compatible application versions, and the folder of an extension or theme.
Gui:Config makes it easier to change preferences that can only be found in the ?about:config?. The extension supports a comfortable way to apply changes to these options. It displays the options, included in the current version, using checkboxes, dropdownlists and textboxes.
Internote 2 allows you to create sticky notes on a web page which will be there once you return. Notes are very customizable, and come with many small, useful features.
MeasureIt draws a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
Menu Editor customizes application menus: rearrange or remove menu items from the main context menu (right-click menu) and main menubar (File Edit View etc.).
Organize Statusbar will enable you to organize your status bar icons. You can now rearrange or remove any item (icon or text) in the Firefox status bar. If your status bar is full and cluttered, give this a try.
Quick Restart adds a "Restart Firefox" item to the "File" menu. You can also use the Ctrl+Alt+R keyboard shortcut, or the included toolbar button.
Right-Click-Link opens selected text in a new tab.
Searchbar Autosizer will allow you to alter the searchbar in that it can size incrementally to each letter, enlarge Searchbar on first strike, or keep the same width all the time.
Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more. It also includes a full-featured session manager.
WindowsUpdate adds "Windows Update" item to the Firefox Tools menu, and launches Internet Explorer to the Windows Update site when clicked.
YouTube mp3 adds a download button to YouTube. By clicking on it you can download the video as a high quality mp3 file.