This question has been bothering me for a while so i am going to just shoot it. The limit on PS3 is 100 as we all know. Sony said max on PS4 would be 2000. So if you have a PS4 and you have 2000 friends and you go to PS3 will it show?
It will show up to 100 friends on your PS3, no matter how many you actually have.
It will prioritize these 100 automatically in some manner, but you can apparently set a manual filter if you always want certain friends to appear.