Yes, and another super cool thing is the prevention of accidental screwups where someone typos their email. If the typo collides with an existing account after

Yes, and another super cool thing is the prevention of accidental screwups where someone typos their email. If the typo collides with an existing account after normalization, it could be (correctly) rejected. Without this normalization index, you could have ronx@gmail pre-existing, someone trying to type "rob.x" typos "ron.x" -- and now a bunch of emails start going out to poor "ronx" (who often doesn't understand what's going on, thinks his account is 'hacked,' etc. Ideally, the system would (for Gmail addresses) reject "ron.x" knowing it's basically tied to an existing user.