Great service, lame extension Rated 1 out of 5 stars
First it's an ugly sized (which cannot be resized) pop-up window which actually loads a tiny web page to save the bookmark.
Fortunately, dev has added ctrl+d support failing which it would have been pretty much useless.
Some features he needs to consider:
1. Resize the CTRL+D pop-up window (or at least let users decide that).
2. Have a separate popup that has all the fields already there like URL textbox and other text boxes like for tags etc. The pop-up should immediately be visible unlike this webpage that loads in that tiny separate window. The focus should be in the text area for tags and once RETURN/ENTER key was hit the the pop-up should go away immediately and do the dirty work (syncing) in the w=background.
3. There should be all those bookmarks on the PC too just like any other bookmark extensions.
4. IF dev doesn't have time to implement this, he could just open the code for this extension(not the service) and instead of people making all those shiny Pinboard extensions which has either one feature or another can rather focus on one (and this is why API is not enough). (I am sure the dev can still count his gold coins)
5. Seeing the Google groups it's obvious the dev doesn't bother to respond. Looks like he already has too many gold coins :-)