Product websites these days offer all kinds of downloadable stuff, from desktops and screensavers to IM buddy icons. How come so few of these websites offer customized WinAmp skins? The one pictured above and installed on my computer mimics a pack of Wrigley gum (you can get it here), but was done by a fan, Denis Bernard. Movie publishers seem to be ahead of the rest; there are skins for Narnia, Corpse Bride, Batman Begins and Troy and a few others that seem to be commissioned by the studios. Pepsi and Powerade seem to get it, too. Most of other branded skins - very good ones, too - are made by fans. There are skins styled after iPod nano, Pioneer, Sony, Puma, Pizza Hut, Nokia.
I think this by far beats advertising through browser skinning.
WinAmp's latest 5.1 version has been downloaded over 4.5 million times. That's only one version for one operating system (Windows) on one site Downloads.com. The first WinAmp was released in 1997. The install base for this thing should be huge by now.