IPv6 was traditionaly carrying only ping6/traceroute6 type of traffic in the 20th century. However, it is not true anymore! While the traffic volume is not high, there are users. An ISP offers anonymous ftp service in IPv6 (e.g. ftp.iij.ad.jp). NetBSD installation in IPv6 is also available. While the traffic level is about 1/1000 of IPv4, IPv6 has already been used for production purpose.
The inbound aggregated traffic measured in every 5 minutes since April 28th, 2001 is illustrated below. The red line and green line indidate daily average and daily max respectively.