That must be new. It wasn't part of esta two years ago. I would be totally unable to produce all my aliases in all the services I have accounts. I wouldn't even be able to remember all the services.
I believe it's supposed to be only names you've gone under, calling yourself horsemaster88 on youtube wouldn't be included, but calling yourself Jerry Fink, lord of horses would be included. With the new laws going into place for giving up social media names I wouldn't be surprised if online pseudonyms will be included in the future though.