The Announcements forum is used for the Scratch Team discussing updates for the website. Most updates are fake. This is why the Scratch Team disabled making new topics, for anyone who is not the Scratch Cat or Gobo.
The forum was created because the Scratch Team wanted to let people know about updates which will help them get more energy units.
This forum has moderate amount of activity because some Scratchers are eager to help the Scratch Team take over the world. However, most people avoid this forum because posting anything disrespectful about the updates will get you permanently banned, by Scratch Cat or Gobo, who have quite a bad temper.