Usage Shown when Not Online

[#1]

I haven't been online in off peak periods and my computer is not left switched on overnight. However, in my usage report I am regularly seeing usage of about 13.4KB overnight, and also about 25.9KB in peak periods when I haven't been using the service at all. Can anyone please explain what causes this usage? I know it isn't much but I am curious to know the cause.

[#2]

Even if you aren't using the connection, if the modem/router remain connected there will always be a small amount of background traffic. As the values are so small (and our packages are Unlimited) there really isn't anything to worry about.