Is TrackBack really a two-way link as envisioned in the original hypertext theory, where both sides know of the existence of the link (as opposed to an HTML link where only one side knows)? People have been trying to emulate that idea by tracking referrers. With some success, but always limited by the nature of referrers: someone has to click, not exactly a two way link. If this is so; very cool. Too bad about the complexity of implementation though.