"Firefox’s Add-ons site has gone social. Firefox users can now maintain “collections” of their favorite add-ons for Firefox, and share with other users. This isn’t just a social feature, though — read on, and you’ll see how this can help you manage your add-ons between computers, too!
"What is a Collection? It’s a set of Add-ons, published on the Firefox Add-ons Web site. If you subscribe to a collection in Firefox, you’ll see the entire collection in your Add-ons manager, and (if you choose) add those extensions to Firefox."
