We wanted to share some of the data we have seen from analyzing signups at scale and insights from great companies like Hubspot.
It is by no means complete, so please share anything you believe is missing.
Also the W3C page about assumptions around names would be a good resource to link.
Great resource and definitely soon good things to add in for names, especially around changing them
I have seen a lot of people suggest blocking all free email domains or only supporting a small subset of whitelisted domains, I expect businesses to see pretty quickly that they lose a decent percent of legitimate signups.
The legitimate signups being the good measure as if you are filtering out disposable emails for instance you will lower your overall signups but should have no negative impact on revenue (potentially positive as people who would signup with disposable accounts now signup with accounts you can contact them on and they are happy to convert to paying with).
We try to make this easy be doing email validation for free at any scale and only flagging the people we are sure are not valid (disposable, unreachable domains etc.)
These days I see more providers going to a strategy of requiring the new signup hit a link sent in a confirmation email. In that case it's possible to accept nearly anything as an email address for signup, without any technical validation, because the ultimate accurate check happens: does the user get the email? Then the business is free to pick and choose and refuse certain domains without having to worry if they are tripping over some subtle aspect of RFCs 2822, 1034, or 1035.