Love what you are doing. I wanted this to exist for so long, too bad did'nt have the time to take it on. I love the fact that you do not have any trace of sender information on the email screen so it is immune to screen capture. How about video screen capture? Have you thought of that?
If you install this Chrome extension, it has the ability to "read and change your data on all google.com sites." Why is this necessary? Seems like quite an overreach.
This permission is required in order to capture text from mail form. Gmail operates under mail.google.com domain. You can examine the extension source code to see that it is not doing anything other than this. It encryptes the content in your browser and sends the encyrpted data to Snapmail servers to get the link.
This is not (or shouldn't be) only for Gmail, right?
We have plans to add other email/messaging services too.
what if i take a screenshot?
I believe the point is to destroy traces of the information, not to prevent retention. For example, I often work with a few associates in a seperate country and there's a MASSIVE language barrier even though they speak english. We use randomly generated passwords so telling them the password over the phone seems about impossible. Theoretically this allows me to securely send them a password that they can easily record for future use. Transmission or storage of passwords over cleartext is generally what you're trying to avoid.