"(Gmail or SendGrid) have pretty sophisticated systems to detect spammers"
Yes, but, the evil genius of the idea is that the email will be from a gmail domain. Emails from gmail to gmail with your own 5 year old account will have a ridiculous conversion rate. In my tests with email, if the email is from the actual gmail domain other carriers TRUST it more. Spam systems rely heavily on DNS/IPaddresses -- and this bypasses all that.
I feel for the smaller email providers. Gmail wont be able to patch this anytime soon, thus, the smaller ESPs without resources will have to change their rules to make the gmail domain less trusted.
Yes, but, the evil genius of the idea is that the email will be from a gmail domain. Emails from gmail to gmail with your own 5 year old account will have a ridiculous conversion rate. In my tests with email, if the email is from the actual gmail domain other carriers TRUST it more. Spam systems rely heavily on DNS/IPaddresses -- and this bypasses all that.
I feel for the smaller email providers. Gmail wont be able to patch this anytime soon, thus, the smaller ESPs without resources will have to change their rules to make the gmail domain less trusted.