We have a 5GB per month plan and never went over it until Dec. Figured it was heavy vacation usage, then was obviously going to go over in January. Started tracking usage and found that when all the computers were shutdown, data was still being transferred, sometimes at high rates, usually (if the time recorded is true) late at night and early in the morning. We did an experiment where we completely disconnected the modem at about 10 pm and saw a data transfer in excess of 150 MB from 5 pm to 5 am with no updates or usage that would account for 150 MB from 5 pm to 10 pm. At no time when we had the modem disconnected did data transfer stop. We are in a rural area and our router requires a PW so it's unlikely someone is "stealing" usage. I put this query into VZ via the website a week ago and haven't heard a thing back.