Two reasons I can think of right away. There can have a policy (and people) to detect abuse and shut off bot accounts, this can even be a separate entity from Y

Two reasons I can think of right away. There can have a policy (and people) to detect abuse and shut off bot accounts, this can even be a separate entity from Yahoo Groups. Second, there can be internal metrics tracking active users and viewed pages, to get down as low as possible before deletion. In both cases archive.org is ruining it for them.