I'm looking for data about #email hosting "market share", and could use some pointers; If you know of a source that matches the following description, I'd appreciate it!
My ideal data source would have a list of email providers and an estimate of how many users (ideally active but I'll take what I can get) each one has.
Some properties I need:
* It needs to understand that email domain and hosting provider are not the same; eg. my work email uses our university domain, but is really Outlook, I need that counted as Outlook
* It would ideally be updated on a frequent basis, bonus points if I can get some level of historical data
* It should capture at least some of the 'long tail' of the email hosts beyond just the giant ones, but I understand that no list like this can possibly be exhaustive
* I would prefer that it be free; I'm willing to pay some, but this is for a personal side project, so I'm not paying for the ones meant for "email marketers", and I can't agree to any ToS that would prevent me from sharing at least bits of the data publicly
Thanks! Boosts appreciated for reach.