The adverts are there because I stopped paying for the ad-free version of the chat software.
The old IRC chatroom isn't really used much anymore - I no longer hang out there.
As part of the upcoming upgrade to the new version of the forum software, I am planning on implementing a new chatroom system for ZooChat - something which will be more tightly integrated with the forum software and give us full moderation capabilities in the chatroom, which will help keep things civil and allow us to apply our community guidelines to the chat as well.
I had been evaluating Slack as a replacement for IRC - and while the software is fantastic and works really well across multiple device types, unfortunately the management facilities and integration capabilities are simply unsuitable for our needs - it is designed as a corporate chat platform rather than for online community chat. So at this point, I don't expect to be continuing with Slack.
Instead, I am currently evaluating using Discord for the ZooChat chatroom - so those of you who are into gaming will probably be quite familiar with the platform. None of this is operational yet - I will make some announcements once the new chatroom is available.