I wanted to put a "recommend to Stumbleupon" link on one of my wikidot pages. (I am a user of a free account). I spent more time than I want to admit looking for how to do this before I noticed that all of my pages ALREADY HAVE a button to cast a Stumbleupon vote with, courtesy of the standard, wikidot provided, bar at the top of my page.
I'm writing this just in hopes that the next person who searches for "how to link to Stumbleupon" or "how to insert Stumbleupon html" will find this post. I did TRY to rtfm, but when clever designers try to make things (wikidot) idiot proof, they sometimes don't quite provide for how clever the idiots (me) can be!