Scott is having issues with his downloads being inconsistent and slow. Leo says that ISPs usually use the phrase "up to" in their claims, and that's usually with the ideal conditions. Leo says that uploading can also slow down his internet access. How does uploading slow him down? Leo says that servers require acknowledgement that his traffic is coming through, so if he's downloading while his data is being backed up, it has to wait for its turn to upload that acknowledgement. This is why Carbonite uses very little upload bandwidth and why it takes so long to back up with it.