To piggyback on my own comment - another possibility is that every site or application with user generated content will eventually be subject to age verification. Meaning that all semblance of anonymous/pseudonymous participation online will disappear. Every username you have online will be tied back to a request token in the age verification database. Those reddit alts you use for porn, your Pornhub account, your LinkedIn, HackerNews, email.. all tied back to your passport.