Why on earth would I pay before even given a slight hint of what it looks like or how it works? A mobile app seems critical as well, but that's highly subjective I guess (since people use CLI trackers..).
It seems somehow like you are riding on the trust that that pinboard guy have gained, and it feels a bit off in my opinion.
Anyway, screenshots or examples please.
Agreed - A demo page would be best, but take a look at pinboard.in/tour/ for how Pinboard does it. You definitely need something along these lines.