I would assume that VW is simpoly using a semi transparent background image on their menus.
This works on almost all browsersd available today, except IE/win (yes that's right, even IE/mac can handle alpha transparent PNGs correctly).
However you can use some intricate filter stuff to mimic the effect also in IE/win. I don't have my bookmarks available at the moment, but I know there is an article over at ALA (a list apart) explaining how to do this workaround as well as a few other places. I even think it's been mentioned before on this forum.
I looked at ALA but couldn't find the link. I thought that as I know where the layers open, I could slice the background picture on my website , and load the corresponding slice into each layer, having given the slice a 'semi opaque' look. The only problem is that the background is random and changes each time the page is refreshed. I want to keep this feature...I think I'll have to create a script to generate the random image and the corresponding random layer slices...anyway thanks again, I didn't thinkl it would be this difficult to find a good cross browser semi transparent background!
No matter how you do it, you have to use layers,
even if it was an image. But the translucence is not in the image.
If you want to mimic that page's translucent effect, it is done by using Layers using a script.