I used facebook way too much and the thing that got me to finally delete my account in 2011 was I had made a post about discovering diaspora and linking my account. Hung out with a friend a month or two later and he loaded up my facebook profile and could see every post I had ever made except the one about a federated facebook alternative.
Veering a little off-topic now, but facebook contacts being my irl friends made that feel so dangerous to me. If half my friends have opinion A and the other half opinion B, then if one opinion is entirely censored but I still see everything posted matching the approved opinion, that will have an enormous sway over how my worldview develops, in a way different from seeing strangers agreeing on those same things.
I get it, but everyone going to gmail is not a good thing and never has been. The paradigm shift is more meaningful than simply growing lemmy as a community. Without that, the only difference from a mainstream social network today would be a handful of big players rather than just one.