This is a really nice idea. If I may make a suggestion, scrolling down takes a lot of scrolling because each link takes up so much vertical screen space on account of really big whitespace gutters, size of the thumbnail, and the general layout. I wind up being able to see only 3 on a screen compared 16 on HN! I would be much more likely to adopt this regularly if you changed the layout to pack more previews in to a vertical screen of space. HTH
Would it work if we had an option for a "compact" mode that shows items without no thumbnail and description?
Or would you change something else?
I don't know if I can get rid of the bottom part with the buttons since this is where the collection selector is - where you pick what collection the item you like should go to.