You have the suffix -let in words like booklet, piglet, ringlet*. I interpret ‘bookmarklet’ as either a small program for bookmarks, or a program that LETS you bookmark articles.
*ME < MFr -el (< L -ellus) + -et, both dim. suffixes
A bookmarklet is an applet, a small computer application, stored as the URL of a bookmark in a web browser or as a hyperlink on a web page. The term is a portmanteau of the terms bookmark and applet.
I think it probably comes from “applet”, which is a small Java program you can attach to an html page.
I created some bookmarklets for personal usage for calling additional French dictionaries from LingQ that are not on the built-in dictionary list, like example sentence databases, conjugations, French-French dictionaries, etc.
You may try them (and modify them if you like) here: http://bit.ly/bHAuZ5
A more detailed article about these bookmarklets is here (sorry, only in German): http://bit.ly/dvWzqb
Important: No guarantee this will work - especially in the future - if the LingQ team changes the HTML structure of their webpages)