I have an uncommon name (not unusual, just not fashionable), and there is another woman out there with the same name. We have almost identical email addresses - one starts firstname dot lastname, the other is firstnamelastname.
I first realised this when I got several emails from her (obviously young) child with their first account and so replied saying I wasn't their mummy and asked them to show my email to their parents and I got a brief thanks in reply.
Since then, I occasionally get the odd email intended for my doppelganger, and it's been like a window into an alt-me social universe - holidays, restaurant bookings, pizza deliveries, that kind of thing. All deleted straight away and I have a terrible memory, so her privacy is fine.
But today's occasional email is about her child's driving lessons - which means that this has been going on for about 10 years now! If this was AIBU, I'd be asking whether it would be stalker-ish to forward this to her with a bit of a "wow, doesn't time fly now X is old enough to drive"? 
Just me, or does anyone else have an online twin? (for all I know, mine is on here, so if you are - hello!)