I don't get it. The only difference I can think of between a LAN and WAN port is that a WAN port would do NAT? (I wish they'd spell it out instead of implying it.) So even if that's the case, it can just do NAT against an already NATted address. Inefficient, but it ought to work.

And what's the deal with this extender-only talk? I thought one of its features was that you could take it with you because it's so small. If you also need an Airport to make it do anything useful, that seems like false advertising.