Thanks to Ma.gnolia’s Mirrord API (which mirrors the Delicious API), a number of formerly Delicious-only applications can also be used with Ma.gnolia. Pukka now ranks among them, though not with out a few discrepancies, notably no support for spaces in tags or ratings, but these are minor issues that can be worked out over time (note, to enable private bookmarks, check this out).
What’s interesting about apps adding cross-domain API support is the slow emergence of standards in new areas (i.e. outside the standard protocols). A framework for application developers that handles multiple bookmarking APIs that essentially do the same thing would be of great value, similar to the work that Jacob Jay started with his MediaSock framework (for publishing to over a dozen media services). I could see such a framework being really useful in browsers, feed readers, media players and similar applications.