All of these add-ons are available on the Mozilla
Firefox add-on page.
1. Stumble, Digg and Del.icio.us Toolbars
These are three separate toolbars but they come in very handy if you use these services on a regular basis. Running all three at the same time will take up some serious real estate on your screen so I would suggest activating them only when you need them or just choosing the one you like.
2. Feed Sidebar
This is a lightweight add-on that adds a collapsible sidebar to your browser. It enhances the RSS feed ability already built into Firefox. Any feed that you have in Firefox through the live bookmarking system will appear in the sidebar. If you have unread articles in that feed they will show up and you can open them all or individually in new tabs or windows.
3. ScribeFire Blog Editor
This is a fantastic add-on if you use one of the major blogging tools. It will integrate with your blog and allow you to create a post right from the browser window you are in. This works well if you don't want to switch the window while you are doing research.
4. Shareaholic
This handy button allows you to share any website you are on with any of the major social sites. This is just like the Share This button that you find on so many blogs. This is a great way to share what you think is great with the world.
5. Better GReader
With this addon (collection of GreaseMonkey scripts) you can customize the way that your Google Reader looks. This allows you to shrink the top and side bars giving you more room to read the blogs in your reader. My personal favrorite addition from this Firefox addon lets you look at the actual page the post is on, not just the text.