What are the pros and cons of using an email address as a user id?

Question

I\'m creating a web app that requires registration/authentication, and I\'m considering using an email address as the sole user id. Here are what I see as the pros and cons (upd

Answer 1

I tend to not prefer pro/con lists, and instead try to think of benefits and challenges.

Challenge:

Some users will be tempted to use their email address from their ISP. Linking to an email alone, may be difficult for the users who forget to update their email in all the web sites they have signed up for before they change ISPs.

Instead:

You should consider allowing a user to provide multiple addresses, as well user-selected id and then let the user decide what they want they wish to do. Perhaps also consider allowing the user to provide an OpenID account.