Does anyone know how 37 Signals built the pop ups for image previews that are now in basecamp? I really like how quickly they load and the fact that the whole page doesn't get "light-boxed" and there is a minimal border It's very snappy. You can see this effect on the marketing page for campfire:
http://campfirenow.com/?source=37signals+home
Just click one of the images below plans and pricing.
Is this custom javascript? Are they using a certain javascript library? Anyone know?