Universal Plug & Play Support will be great for users who are stuck behind their router, they wont need to reconfigure their router or use WormNAT.

Would it be possible to implement it in 4.0?

Sure, I don't see why not. 4.0 will come with brand new network code, so one would be able to change the port for incoming connections :)

uh upnp doesnt work for EVERYONE so its only a soloution for some :P but then again i now know how to port forward lol...

will we be able to make the game use a common port like port 80?

80 would still need forwarding, the exact reason that you can't run a web server behind your router.

Most, if not all routers nowerdays (Apart from cheapo ones) come with UPnP. My Belkin one must be 2 years old now, and that has it.

You will also find UPnP helps if you use Windows Live Messenger.

will we be able to make the game use a common port like port 80?Yes. You will be able to set the port to whatever you want.Sure, I don't see why not. 4.0 will come with brand new network code, so one would be able to change the port for incoming connections :)

Security, anyone?
Unplug n' pray (http://www.grc.com/unpnp/unpnp.htm)

Security, anyone?
Unplug n' pray (http://www.grc.com/unpnp/unpnp.htm)

It will obviously be a toggle option.

Not just that, thats just Window's thing, doesnt affect games. And we all know how buggy Windows is, I wouldnt be supprised if there is a security flaw in Paint.

my router "netcomm nb1300 plus 4" has no support for uPnP... unless thats only for winXP PRO in wich case its understandable for why i cant use it...