If you read here you will see that there are many active groups. Even of those that aren't active, some have important history, even scientific value. As for

If you read here you will see that there are many active groups. Even of those that aren't active, some have important history, even scientific value. As for old posts disappearing, individuals have always been able to go to Yahoo Groups and delete posts that they later thought the better of. Group owners can also delete posts.