i was just checking the myst 4 website
http://www.mystrevelation.com/teaser/uk/
and notised a little button in the middle of the screen marked "bonus"
you need to solve the puzzle in the browser to get the "bonus" it's pritty cool.
you get some nice desktop wallpaper.
just letting you people know incase you did'nt notise it.

[Bard09]

Where do you solve the puzzle? The button is greyed out for me...

on the left hand side of the screen, there should be 3 buttons (you cant press them, but they can be changed)

[kingBLAOW]

You just need to mouse over them in order to solve the mini puzzle.