I run NetWorx in the background and haven't looked at it for months. When I did today I noticed that starting May 13 of this year my daily usage jumped from 60 to 90 MB a day to 3 to 13 GB a day (that's G as in gigabytes). My monthly totals have gone from 3 to 8 GB a month to 190 GB in June. That can't be because my monthly ISP limit is 10 GB. I am monitoring only my own computer.
NetMeter shows 3 GB in June, and no quantum change on May 13.