Right now you cannot save and continue adding things. If you save you have to leave and edit. I assume this is something that would be fixed...but, just in case...
It would be great if is automatically saved on its own, like googledocs does.
The plan is to minimize clicks and user errors. So not many "Save" buttons
One thing that will help towards this, is that the search will produce links which you can just "add to " and the collection you want (or the "basket" which will serve as a temporary collection to save links found when you are just browsing the web)
Then, just edit the order of links (if you need) and .. no save :)