The latest at 3 Spots is a how-to for the category method which is in use there. A 3-part how-to for a 3-part hack. You'll need a collapsible sidebar, bookmarked posts in the social-bookmarking service of your choice, and the ability to pull linkrolls or content feeds from the service that you select in order to build the collapsible sidebar. All explained very clearly and in a way that encourages customisation / application to your favorite social bookmarker...
Filed in: freshtags, blogtech, webtech, categories, blogger-hacks, del.icio.us, netvous
Yes I do encourage people to try other social bookmarks, I just find it a petty that most category tutorials only talk about del.ici.ous, like if it was the only possibility when most can be used. Why not give a chance to new commers? (OK the database is smaller but you can import, ...well in most you can. :S)
I've asked Furl, Blinklist and a couple of other about JSON support and not heard anything back.
In your research, have you come across any talk of supporting JSON from the other players?