If you have gmail.com mail (or similar), you can compose and read the related e-mails entire online, via your browser. Other than appearing on your display screen, those e-mails never leave gmail.com's server.
Terrorists use the "shared draft folder" method to communicate without actually sending an email. All the network traffic is browser traffic.
Supposedly, the harassing emails sent (supposedly) by Broadwell to Kelly were anonymous / anonymized somehow. If Broadwell sent the harassing communications from the same gmail.com account she used to communicate with Petraeus, well, "stupid" comes to mind, unless she intended to associate Petraeus with the harassment, along with herself.
If Broadwell sent the harassing communications from the same gmail.com account she used to communicate with Petraeus, well, “stupid” comes to mind, unless she intended to associate Petraeus with the harassment, along with herself.
I don’t think she is that stupid. Presumably the FBI tracked her IP addresses and got a court order for all her other email accounts. Or maybe the whole FBI story is a fairy tale. Who knows at this point.