The paid service involved in the leak was known as the "2channel viewer" (), or . Its main utility was that it allowed users to read old threads; if a thread on 2channel received 1,000 posts, it would become part of the by a process of ".dat omission" () of such threads, after which time a thread was no longer freely accessible. 2channel charged per year for the service, which was typically paid by credit card; logs of these payments were the source of the data leak.