alt Hacker NewsYou've got it - subdomains are sufficient (IIRC). Something like notifications.mycompany.com for the important stuff and news.mycompany.com for the more marketing stuff (and of course someone.else.entirely for the the cold email list "well, surely this one little list couldn't hurt" ... nah, who am I kidding, never use those)
subdomains are not sufficient, unfortunately. I think the instance I'm thinking of is technically web/https (chrome's site safety feature where you can specify a domain as 3rd party content- so when something gets flagged uour entire domain doesn't get blacklisted)- but it's much easier to just grab another domain