Weave is a feature by the Firefox team that will allow you to see what tabs was last open in the last browser you used, and be able to open at the browser you are using at the moment.
This is particularly useful for mobile devices, meaning you cna continue reading on your handset what you read on your desktop, and vice versa when you arrive at your destination.
An early implementation of this feature has now reached Fennec, allowing a user to see a list of tabs open on another browser and open them on your Fennec browser on your handheld.
The UI is currently a bit rough, but this will be improved soon. The developer is also looking at synchronizing thumb nails instead of only text, but this has so far not been implemented.
Read more at Jono Scriptâ€™s blog here.