Commonly you know someone’s name and company they work at, but don’t know their e-mail address. Sometimes if you know other e-mail addresses within the company you can decipher their particular naming scheme (i.e., firstlast@company.com, flast@company.com, etc.)
It should be possible to send an email to simply: “joe shmoe”@company.com and have the MTA automatically forward it to Joe using an internal corporate database.
Of course, spaces and quotes are not valid for e-mail addresses.
