Everybody at aol stopped using it years ago for internal communication and switched to slack.

The team had also been cut down to a skeleton crew a long time ago and they stopped development on it.

The reason why they are killing it as opposed to letting it hang around for ever is that aol has been in a multi-year long process of moving everything to AWS and due to the way aim is architected, it would be a major development effort to make the move, and they just don't want to spend the money.

I'm going to guess the mail product will also face a similar end for similar reasons.