Seems that email is the unifying online id and emphasizes the importance having an email address at a domain that you own and control so that you don't lose it

Seems that email is the unifying online id and emphasizes the importance having an email address at a domain that you own and control so that you don't lose it when these social networks disappear or violate your privacy to the point that you need to walk away. Would it be worthwhile to have a service that managed all of your online identities? You could register multiple avatars/aliases and the service would create email addresses for each of them that could be used to sign up for different networks. Then all of those email notifications, etc. could be forwarded to one confidential email address at a domain that the user owns and registers with the service.