My opinion on “throwaway email addresses”:
From the users’ point of view (as I’m a user on several social networks and communities myself) I want to keep control over the websites who have my personal data and over the emails I receive. So as soon as I’m using a throwaway email address I’m aware of the consequences that I might miss relevant information.
From the communities’ point of view I’m with you: I’d very much prefer to have a 100% certainty that all email addresses are valid and regularly checked so my efforts regarding engagement, activation, gamification etc. aren’t lost on them.
My approach as the community admin is: I don’t limit the users’ ability to use throwaway email addresses as this shows they are taking active steps to protect their personal information and (inbound) communication. And because they are doing it, I need to assume that they aren’t really open to my efforts of keeping in touch with them in the first place. So I’m saving myself the trouble of creating a blacklist when this would lead to two things:
- Less users registering (because the users go away when they realize they can’t use a throwaway address)
- More of the community’s emails are being sent into a black hole (personal filters in the users’ email programs)