If my calculations are rights I believe that in the main site Mathematics Stack Exchange there are at least 200000 users whose reputation is 1. My belief about this situation (I haven't stats) is that the most of these users are persons that in the past have been created an account and after they have little activity.
I believe that the issue (by the nature of the problem, say us the willingness or motivation of these users) isn't of the site Mathematics Stack Exchange, but I would like to know if it is possible to promote some solution, and what.
Question. I believe that that there are a huge number of users with little activity, or none, in the site Mathematics Stack Exchange. Is it possible any constructive solution to encourage (the return to the site of) these users? What? Many thanks.
As motivation I am saying that I believe that it is a real problem, a great number of persons that have been created an account because they were motivated to learn and share mathematics, but that today they seem disconnected to the site.
The solution that I propose, if as community it is possible to promote some solution and put this (the solution that I evoke) one to work, is to
send an email as reminder that they are welcome to the site or maybe a special Newsletter containig special and selected math content from the site MSE.