I have been clued in to thickbox thanks to Jeremy Palmer who is using thickbox for http://searchmarketingvideos.com/.
If you are an affiliate marketer working on a landing page then thickbox fits the bill perfectly. If you are focused on selling something then you really don’t care what flavor of web 2.0 technology it uses (Jquery) but rather that is quick to load 20k compressed and that its easy to use(very)