Today the Copyright Alert System was switched on today affecting most ISP's in the United States. Essentially what is happening is that P2P networks are being scanned and if it determined that you are sharing or downloading copyrighted material then you are subject to the new system. What does that exactly mean?
If it is your first offense then they will let you know that a copyright infringment may have taken place. They will also educate you on how to legally download content. If this is on ongoing issue your ISP can do a number of things including but not limited to throttling your internet connection speeds or redirected you to a default page that requires you to contact them regarding this matter.
So you never download any content illegally? Then you are clear right? Wrong. If your wireless network is unsecured then anyone can use your internet to download content illegally and you can be held responsible. The first step is always making sure your wireless network is secured. The second step is educating everyone is the house with regards to downloading content illegally. If you have teenage children maybe consider creating an iTunes account for them with a set spending limit on the account to allow them access to digital content.
For more information on the new Copyright Alert System go HERE.