Can people on the internet spy on my network shared folder?

I was wondering if people out on the internet can spy on my shared folder somehow. That won't be good. My network is on one of those D-Link gigabit gaming routers.

I've been doing this for years but I just had a scary thought when I was readint some VPN (Virtual Private Network) article, that maybe people from the outside of my router can gain access. Can somebody tell me if my files are safe or not?

Thanks

If you have NAT on your router, then it is unlikely, unless you specifically forward 137-139 and port 445. even then, some isps specifcally block those ports

Cool, it as NAT so I guess I'm good then. Thanks ;)

Not by default they can't. But if they join your network they can. Not likely to occur through the internet, but if you use wireless etc. then it's more likely.