If you have tested IE8 beta you might have already know what is activities and webslices. Those are the most interesting features of the IE8, if these features interests you, you can get the same functionality in Firefox too with cool new add-ons released by Firefox developers.
Activities are contextual services to access web services [...]

gDocsBar is a Firefox extension that shows your google documents in the Firefox sidebar. If you are a google docs user you will love this add-on, with this installed you no longer have to keep the tabs open.
After installing the extension, login to you Google Docs account, don’t worry your login credentials are sent directly [...]

There is a security hole in SmugMug, discovered by Google Blogoscoped which allows you to view or even download private albums. SmugMug users can protect photos from public view by selecting private option, one would expect these won’t be viewable by public. But that is not the case, any one can view these photos by [...]

Shareaholic is a Firefox extension for sharing content to social bookmarking sites easily.
With sharaholic you can submit the sites you are browsing to all your favorite social bookmarking sites, you can also email the links to your friends.

Shareaholic supported sites:

Email This is a Firefox extension which allows to share the link, title & text of the web pages you are viewing with your friends. Email This supports Gmail Google Apps Mail, Yahoo and Desktop clients like Outlook express & Thunderbird.
How to use
For Gmail, Yahoo & Hotmail
Compose-Message page will open in a new tab.
The [...]

Meebo is a great way to use all the IMs when you are in office, i use meebo regularly in office.
meebo Firefox extension allows to run meebo right in sidebar. You can see all your contacts, login to different IMs and keep in touch with your friends.
If you are a regular meebo user [...]

DownloadHelper is a Firefox extension which lets you download web content like videos and images. What is unique about this is you don’t need to copy and paste the URL from YouTube to another downloader tool, you just need to click the downloadhelper icon to download the video.
After installation the extension will add a small [...]

deliGoo is a Extension for your blowsers Firefox and IE6.0+, for power users of delicious to quickly find bookmarks from delicious. Either you can search for specific users bookmarks or just delicious tags, results are displayed through Googe Custom Search.
This is quite useful service if you use delicious regularly. After installing the extension you [...]