Today we’re excited to launch ordered collections. They’re like the regular collections you know and love, but with a few extra bells and whistles. Ordered collections allow you to specify a particular order in which notebooks appear, giving your collection more structure and a clear flow. They also help guide your readers through your notebooks in the order you intended.
Check out this notebook for more details on the specifics of ordered collections and let us know what you think!
Thanks! As I’m very often doing the small dance (open the notebook I want to put first, remove it from the collection, then add it again) to keep a certain notebook at the top of each collection, this is very good news.
I feel it should not be an option, but available for all notebooks. What is the point of having “non-orderable” collections?
The only downside currently is that it forces the presentation to small previews — I like the large previews display better. Can we have all the things? 
Hi Fil! Thanks for the feedback!! Happy to hear ordered collections will be sparing you from removing and re-adding notebooks back to the same collection. 
I think regular, unordered collections will still be useful for some folks using collections mainly as a means of organizing their notebooks into related topics (more like a personal file system), but ordered collections will definitely be the way to go for anyone looking to add some chronological structure, tell a story, or really just present their notebooks with a clear flow.
We currently only have the list view, rather than the larger grid view, available for ordered collections to make the notebook order more intuitive and straightforward, and to make the act of reordering notebooks a bit simpler (it currently mirrors the same reordering pattern that notebook cells have), but the larger grid view is definitely something we’ll add to the feature request list. 
Another way of thinking about this, maybe, is that “unordered” collections are currently “ordered by added datetime”. What’s different (from the pov of the user) is that, while “ordered” collections offer a clean UI to re-order, “unordered” collections offer only a clumsy way to do so.
It seems to me it would be simpler and clearer to make all collections re-orderable, and maybe to order them “by added datetime” by default — this would unify the experience, and the user would not have to decide on an ordering mode, but only on the order. The real choice would then be the default presentation (by list or grid).
Ordering would still be optional, and, on collections where the order does not matter much, I would move notebooks only when I see that the current order is “wrong”. Most of the time it’s when I add a notebook to several collections, and see that it appears at the top of each, making the page that lists the collections boooooring. In terms of UX it would also be nice: the action would be made at the same place where I see that the order is “wrong”. (It would also be lovely to be allowed to re-order collections.)
I have of course no idea of the feasibility server-side.