SimilarWeb allows you use the extension interface for both browsing and voting instead of being limited to a web-based directory. Once you have the extension installed, using it is as simple as clicking on the SW icon beside the address bar. You can rearrange the suggested order of sites, submit new sites, and vote a suggested site up or down based on relevance.
Feed Sidebar
The Feed Sidebar is an extension for Firefox that displays the items from your Live Bookmarks in the sidebar. It is intended to be a lightweight extension of the RSS capabilities already included in Firefox, not a completely new feed management system.
All-in-One Sidebar (AiOS) is an award-winning sidebar control, inspired by Opera’s. It lets you quickly switch between sidebar panels, view dialog windows such as downloads, extensions, and more in the sidebar, or view source or websites in the sidebar.
Works with:
Firefox: 1.5 – 3.0a1
View and manage downloads from a tidy statusbar – without the download window getting in the way of your web browsing.
Despite its compact size, Download Statusbar packs in more useful features than the standard download window. The fully customizable interface auto-hides when not in use, allowing full control without interruption.
Works with:
Firefox: 2.0 – 2.0.0.*
Download:
Gmail Manager allows you to manage multiple Gmail accounts and receive new mail notifications. Displays your account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets
Works with:
Firefox: 1.0 – 2.0.0.*