No! NO NO NO. Not 5. He said 10. Nobody's doing 5. Who uses email for 5 minutes? 10's the key number here. 10 commandments! 10 doors! 10, man, that's the number. 10 chipmunks twirlin' on a branch eatin' lots of sunflowers on my uncle's ranch! Step into my office!

You could test it with Google Adwords. Put up ads for "10 minute mail", "5 minute mail", "30 minute mail", and "42 minute mail", and see which one gets the most clicks.

I heard Tim Ferriss claim that this is how he picked the title for his book, "The Four-Hour Workweek".

On the other hand, you could also just pull 10 minutes out of the air and say "that sounds about right". Which it does.

Common Man that's just stupid, nobody will buy that!

umm, i think to improve the service you want to increase the expropriation time of the e-mail address. so "why stop as 10 minutes! Whats about 15 minute e-mail? ;)