All messages are encrypted to ensure only the right person will read it. Anyone intercepting a Hisser message won't be able to tell who the message is for and who has sent it.
The built-in spam protection makes sure only the people on your contact list will be able to send you a message.
Hisser allows you to run your own server and to manage your own users. This makes you completely independent from any organisation to use Hisser.