What is the difference between software registration and product activation?

Difference between software registration and product activation

Software registration Product activation
Software registration is a methodology  that involves the submission of some necessary details of the software user, which is submitted to the software designers or software developers Product activation registration is a methodology that is compulsory related to some software that is used by the software designers or software developers the ensure that the user will not install that software on more PCs until it is legally licensed to use.
Software registration is optional. Product activation is mandatory.
Software registration is helpful to get product software support. Suppose a  software can run in a fixed number of times and then the software user is restricted for more use and has limited functionality or will not run until it will be activated through phone, Message or with some another method.