I spent 4 months regularly posting why I was leaving Facebook, and that I would like to keep in contact with all of my friends, and where they could find me. I kept it short, and posted it regularly. I found that about 50% of my connections followed me over. Of those 50%, about 20% made a permanent switch themselves. Then you could watch waves where engagement was high, then would trickle to a minimum. Then it would ramp up quickly again. Which meant facebook did something new to piss people off.