Mailjedi is more secure for e-mail

MailJedi is built on the idea that the main threat comes from the intendended recipient.

From the press release:

It's a free service that innovates the way electronic communication occurs. With MailJedi messages are displayed on
secure webpages which allows the sender to fully control the message. The recipient receives a private comment and the link in their inbox. The sender can track when the message is viewed, delete the message easily at any time, modify the message after it is sent, and block forwarding. In a society where email is increasingly used as evidence MailJedi offers an easy communication
solution for anyone with sensitive information. The service is free and users sign-up in less than a minute with an already existing email account.

An article about the service can be found on Datamation.