2ch operates on innovative forum software which is a major departure from 1980s bulletin board systems or 1990s forum software such as vBulletin. Most importantly, nearly everything is done anonymously and voluntarily. A posting in a thread will either "age" (bump, from Japanese "ageru", to raise) or "sage" (not bump, from Japanese "sageru", to lower) its position in the thread list; "sage-ed" posts have no effect on its position. Threads may be "sage-ed" if the thread is disliked, or to keep it from cluttering the main thread list, or to prevent idle browsers from flooding in and trolling the thread at the top of the list.
Each thread is limited to 1000 postings at maximum, and a new thread must be opened (by some anonymous user, self-elected during discussion) to continue discussion. This prevents the rotting of old threads and keeps active topics refreshed. It also saves bandwidth, which is a major concern on a forum as large as 2ch. Old threads are moved to a paid archive, then eventually deleted.
With the huge popularity of this forum, the style of web forums with anonymity, index, and sage features is now known as "2ch-style"[citation needed].
Q: Why did you decide to use perfect anonymity, not even requiring a user name? A: Because delivering news without taking any risk is very important to us. There is a lot of information disclosure or secret news gathered on Channel 2. Few people would post that kind of information by taking a risk. Moreover, people can only truly discuss something when they don't know each other. If there is a user ID attached to a user, a discussion tends to become a criticizing game. On the other hand, under the anonymous system, even though your opinion/information is criticized, you don't know with whom to be upset. Also with a user ID, those who participate in the site for a long time tend to have authority, and it becomes difficult for a user to disagree with them. Under a perfectly anonymous system, you can say, "it's boring," if it is actually boring. All information is treated equally; only an accurate argument will work.