As many will have discovered, if you’ve been away from the forum for a while it will send an email with a digest of recent activity. Mine is set to weekly which is I think the default. Please update your preference if you like - I wouldn’t want anyone to be annoyed by the forum’s emails.
The Settings page, which has an Emails tab, is found at the top of the notifications menu: click on your profile at top right, then the cog wheel.
Or here:
https://retrocomputingforum.com/my/preferences/emails