The indefatigable John L. Clark recently announced another very useful effort, the start of a system for managing your del.icio.us bookmarks as XBEL files. Of course not everyone might be as keen on XBEL as I am, but even if you aren't, there is a reason for more general interest in the project. It uses a very sensible set of heuristics for mapping tagged metadata to hierarchical metadata. del.icio.us is all Web 2.0-ish and thus uses tagging for organization. XBEL is all XML-ish and thus uses hierarchicy for same. I've long wanted to document simple common-sense rules for mapping one scenario to another, and John's approach is very similar to sketches I had in my mind. Read section 5 ("Templates") of the XBELicious Installation and User's Guide for an overview. Here is a key snippet:
For example, if your XBEL template has a hierarchy of folders like "Computers → linux → news" and you have a bookmark tagged with all three of these tags, then it will be placed under the "news" folder because it has tags corresponding to each level in this hierarchy. Note, however, that this bookmark will not be placed in either of the two higher directories, because it fits best in the news category. A bookmark tagged with "Computers" and "news" would only be placed under "Computers" because it doesn't have the "linux" tag, and a bookmark tagged with "linux" and "news" would not be stored in any of these three folders.
XBELicious is work in progress, but worthy work for a variety of reasons. I hope I have some time to lend a hand soon.