You might have missed that Google already does this. They literally already do this with the + markers. Literally all that is necessary is for the user to be

You might have missed that Google already does this. They literally already do this with the + markers. Literally all that is necessary is for the user to be allowed to add an entry saying kasdlfj33sdfsketchy = johnsmith23+sketchy so that the user can give out "kasdlfj33sdfsketchy@gmail.com" rather than "johnsmith23+sketchy@gmail.com" as the user can do today. Nothing that you have stated is difficult or a choice, because johnsmith23+sketchy is live today. If you have a gmail account, you can give out your accountname + marker to anyone you want, so that later you can start filtering it. This is security by obscurity, since this can be removed by a regex. I would like them to fix this. As for your other point, where you call the extra data "nontrivial", I am afraid you are wrong, it is almost the definition of trivial. If you have a gmail account, go to it and type a name or any word into the search field. You will instantly receive search results from the entire history of your email archives. That is because your email archives are fully indexed for fast searching. This takes a not-insignificant amount of space. Adding a few bytes of aliases is absolutely trivial compared to the amount of storage and lookup that Gmail does on your behalf. It's almost the definition of trivial. This isn't 1964!