In Japan, most ISP have deployed a fiber network to offer ultimate transfer speed of dozen of Mb/s for their customers, allowing in consequence massive data exchange between users. To save performance as well as prevent illegal data transfer (Can we really do it?), NTT decided to limit the upload to 30 GB per day. Of course such restriction will not affect normal users, but only a small percentage of users who took advantage of the performance level of a fiber network to exchange massive amount of data (legal or illegal). Such decision was of course quite heavily criticized in Japan.
[translation by Linathael]