Well, I guess you were all invited by Twitter today via a pop-up window to be found via your email address.
When you click the blue question mark icon, you’re sent to this post on the Twitter Support forum regarding ‘contact discoverability’.
Is that really the purpose or is there more? I already got two DMs today from people that had their Twitter account hacked and had to create a new one. They did because they have no idea what to do if you want your account back.