One solution is to expose the JavaScript bookmarklet snippet on the page. Then the user can bookmark a dummy page, like the one they're currently on, then edit the URL of the bookmark to the JavaScript.
Some popular bookmarklets are being collected on the page below with that purpose in mind.
Some popular bookmarklets are being collected on the page below with that purpose in mind.
http://static.chrisbray.com/bookmarklets/
Edit: Based on the bookmarklet's div in the video, I'm wondering if you're using Instapaper for your data store? If so, have you had any issues?