all of the people that are wished happy birthday by the forum were once players of this mod. they may simply have forgotten about it in the many years since they left.
A simple email saying hello might be all it takes for people to remember and come back to say hello, or even (hopefully) to stay a while and start playing again.
a particular saying comes to the foreground here, and that being "out of sight, out of mind"
an birthday email has made me revisit a lot of communities id simply completely forgotten about.
the untapped potential is quite high, sure they may just delete the email, but they might not, and more players is desperately needed for this mod.