Certificates not just encrypt communication, they also tell that the site is really the one you think. In that sense self-signed certificates are mainly useful

Certificates not just encrypt communication, they also tell that the site is really the one you think. In that sense self-signed certificates are mainly useful for small amount of people when you have another way to validate that the certificate is valid (i.e. installing it in person in the intended client devices). Else anyone could just create another certificate with the same human readable info. There are some free or cheap enough certificates around that are already suggested, and other ways to validate certificates that may be useful even for self-signed ones, like http://convergence.io/ http://convergence.io/