http://zqktlwk5ilgohy63eyrptyb4mc76bunfmxcnstkmveyjnskxkpq3b5yd.onion/wiki/Anonymous_Communications
Worse still, the mainstream webmail services typically offer other services that "conveniently" allow you to share the same account/cookie between them. For this reason, if you opt to use a major webmail service, you need to be careful with things like entering your street address/zip code into their corresponding mapping services , or for that matter, ever using a yellow pages .