Duplicate Pairs

Summary

A duplicate pair is two bookmarks which take you to the same url, that is, the same web page.  This generally means that they have the same url, but Bookdog digs a little deeper than that, because bookmarks with similar urls can also take you to the same web page.

Some browsers and services (Google, del.icio.us, Firefox 3 and later) do not allow duplicate pairs.  If you create or import a new bookmark into one of these browsers or services which forms a duplicate pair with an existing bookmark, the existing bookmark will be immediately and silently deleted.  If you create duplicate pairs in one of these documents in Bookdog, Bookdog allows you to keep them until you Save (upload) the bookmarks, then deletes them.

Details

Regular and Feed urls.  Firefox live bookmarks have a url and also a feed url.  So, Bookdog considers both in making its comparison.

Canonization.  Both the (regular) url and the feed url are canonized (or if you prefer, canonicalized?) to remove trivial differences which are ignored by the internet.  The canonization process involves:

Comparison.  Following the canonizations, Bookdog applies the following algorithm to all non-empty canonized urls:

  1. If the feed urls are different, the pair is not a duplicate.
  2. If the regular urls are the same, the pair is a duplicate.
  3. If the regular url of the first bookmark is the same as the feed url of the second bookmark, or vice verse, the pair is a duplicate.