Is emailing them back then and asking them to add them an ok practice?
Awesome, thanks for emailing .... talk about things they talked about ...
Also, I'm starting up / have a product focused mailing list for updates, features, and other closely related topics, no sales.
Can I add you to this list? I also have a separate one for sales and deals if you would like to be added to that as well.
(Notice the ask starts a new para)