Can someone else have the exact same gmail address as me?

The googlemail version of your address is the same inbox too. And anything you add after a plus sign, just before the @, gets ignored, so yourname+shopping still arrives to you. Handy for spotting who sold your address.

no. every gmail address is unique, and dots don't count, so john.smith and johnsmith and j.ohnsmith all land in the same inbox. yours. if you're getting someone else's mail it's almost always them typing their own address wrong when signing up for stuff. happens a lot with common names.