Yeah, Rowan, the sandisk site says "Linux and Mac OS® X v10.1.2+ (U3 functionality is not supported under Linux or Mac OS (any version), but device is MSC." And I was wondering WTF this "U3 functionality" was that wouldn't be supported on my Macs.   

As long as this U3 thingy doesn't take up any sizeable portion of my 8 gigs, I'm fine with not being able to use it. But what the heck would it do if I could?