At SDPHP we are starting an open source project (grouptopics) for user groups, but that is for another post.
We are setting up oAuth authentication with Google, Twitter, and Facebook. While doing so, the developer that did the initial integration stopped with the Twitter integration because they do not give you an email address, and he is steadfast that an email address should be required for a user.
I have thought a lot about this lately, and I am of the personal belief that an email address is not required. While I would like to have one for communication, the main goal is authentication. Having the email address does nothing to accomplish this authentication, it just serves our greedy desire to send emails that are probably unwanted.
I have not given any final direction towards the group. What are your thoughts? Do I listen to him and require it, or go with my gut and say that it shouldn’t be required?