It's sage.
Boards in the textboard software have their threads sorted by the time of their last post, so making a post would "bump" (上げ, age) the thread to the top of the board index. However, when posting in a thread, users may use a function known as sage (下げ, lit. lowering) to avoid bumping a thread in this way. Often, posters will use sage on purpose, to avoid unwanted attention.
VIP or Vipper is a shared nickname that was used by 2ch.net users.