1. I use the bookmarklet to add bookmarks
2. I write a short description for the bookmark
3. I click on one of my existing tags or add a new one
4. The Pinboard organize tool shows a preview of the content so I can edit bookmarks quickly
5. Automatically archives my retweets and links posted to Twitter
6. Let's me have private and public bookmarks
Just sayin' for me bookmarking is a solved problem.
Personally, I don't want something with unique UI features like folders popping up on my browser window. That just interrupts the workflow I've already developed.
I also appreciate that I paid for Pinboard and can reasonably expect it to be around for awhile without getting acquired or shutting down.