Mozilla's updated its Collections tool for sharing and packaging add-ons, making it easier to add an extension to your Collection from the main add-ons site, offering more detailed permissions for sharing your Collections and a simple "Favourite" system for creating instant collections.
The changes to Collections are outlined at an official blog post in a nifty HTML5 video, which we can't quite get working through an embed here.
For casual users of Mozilla Collections, the main benefits are the ease of which you can add an extension to a Collection — it's now just one button press. And if you don't want to even bother creating a Collection, you can still benefit by marking extensions as "Favourites", which creates an instant, no-hassle collection of My Favourites that you can later use to re-install Firefox or share with friends.
We have a few of our own Lifehacker Collections, some now in need of real updating. If you've got your own impressive add-on pack to show off, share it in the comments.