Networking, Can shared files be seen on the internet.

I think this article that I got at MSN will help. The answer is yes and hackers look for networks.

http://computingcentral.msn.com/guide/mastercomputing/#connecting

Connecting Safely to the Internet  

Many people know about the risks of downloading and using unknown software without first checking it for viruses, but did you know that you may put your computer at risk just by connecting to the Internet?
If you have a Windows 95/98 local area network (LAN) at home, you probably use "File and Printer Sharing for Microsoft Networks" so other computers can share your files and peripherals. The problem is that your Internet connection can function as an extension of your LAN, allowing millions of Internet users potential access to your computer. That's why LAN users need to protect themselves. So take a few minutes and follow these simple steps to keep your computer safe.

First, find out what protocols (the language computers use to send information over a LAN or the Internet) your computer uses by clicking on Start, then Settings, then Control Panel and then selecting Network. You probably have several network protocols. Select the TCP/IP protocol associated with your network card and click Properties, then select the Bindings tab and uncheck the boxes. Then click on OK. Windows will display a warning telling you that you "have not selected any drivers to bind with" and asking if you would like to select one. Click No, then restart your computer.