And you can also interchange `gmail` and `googlemail`, append `+anything` to alias.
It's a slippery slope though - forget worrying about remembering or managing passwords, you have to deal with variations of an email address too.
Further, email clients will reply from whatever address you used to setup the client. Maybe you can add aliases, but that will be time-consuming, and even where supported there's usually a single-digit limit. This can cause real headaches - e.g. "reply with `UNSUBSCRIBE` in the subject line to be removed from this list" and being unable to reply from the right email address.
This is true in general, but some of the very early Gmail addresses do differentiate based on the '.'
For instance, my very early-adopter Gmail address has a '.' in the address but it is an entirely different account from the one without. If you send mail to the one without the '.' I do not receive it.
