> Modern desktop Macs come with a five button plus scrollball 
> mouse, so it's not much of an issue. Not that I can 
> understand how it is possible to actually use the two side 
> buttons - I set them to do nothing for my own sanity.

They're for forward and back in your web browser using your thumb, at least,
that's what mine are for.

Ramon Leon
http://onsmalltalk.com