We've probably all seen this:
What's the deal with that? I know I don't have a static IP on my router but I would think that I should at least be able to use the dynamic IP (whatever it may be at the time) to connect... I would guess it's more than just whether it's dynamic or static, but what might that 'more' be?
Your desktop is only reachable over the local network. Others can access your computer using the address localhost.