Overlay Text over text only

Hi,

I’m looking for a solution to do this :

Only on some words, I’d like a small popup open automatically.

But I’m looking for a plugin to do it, there is lot of overlay or lightbox, but always on image, and also impossible to put text and image, or text only.

To have an idea about what I’m looking for, just visit Wikipedia page, and hover mouse somes internat links, it’s just fantastic ! Exactelly what I need.

A small popup with text and/or image.

Is there a plugin to do that ?
Thanks for your help, or for ideas.

The page I need help with: [log in to see the link]