It's intentionally non-social, your stuff is yours. It doesn't require a redirect when adding a bookmark, and in general I find it simpler and quicker to work with than delicious (especially the newest version).
I never claimed it was entirely unique. Bookmarking via a bookmarklet has been around a long while. I took ideas from several places, and then trimmed it down to the simplest set of functions that solved my problem.
sorry man, not trying to bash your idea, but it's been done before :-/.