This is a wireless encryption security protocol. If you are connected to your router over an ethernet cable, you can shut down the wireless activity of your router altogether. If you are connecting over the air, then you normally have a choice of WEP (the original encryption mode, now quickly cracked by standard software packages) or the newer WPA algorithm (which will be replaced Real Soon Now, since experience shows that it offers much lower security than the designers claimed). I bought my router early this year, even though a check of user comments on http://reviews.cnet.com/Networking/2001-3243_7-0.html?tag=cnetfd.dir showed that the WPA implementation crashed every 15 minutes on that model. But I just played with the wireless and depend on cable.

Ihe crash just caused an immediate reinitialize and reconnect. Not a big problem, but it indicates just how early it is for real wireless. By the end of the decade, it will work. But everybody recommends some security on your system. I have never read a good explanation, but I did come across a mention in one article that said that Starbucks had some special security software to reduce security risks caused by their open wireless connections, so I assume there really is some problem, even if the experts don't spell it out.