This is just a solid idea and product, and is something that should have been baked right into email protocols from the start. It's growing fast, but I hope the online advertising industry gets wise to this soon so I can get more Credo!
Using it for few months and it saved me a lot of time and also earn me some cryptocurrency through paid content that was sent to me - which actually work cause I read those mails since they stood out from the others I usually recieved as whitelisted.
I work at a company, where one of my duties is to select and train interns for the department. I get their CVs through a particular system, and if it satisfies our needs, I send the potential intern an email inviting them to an interview. Two times now my emails have bounced back because of your system. I suggest you fix your filters.