I keep good contact with DD2's old fc's, and I send updates to DD1's old fc's as well, although less often. They were both amazing and i really couldn't bear to lose the contact, they are too important to DD's and important to me as well 
I actually think i spend quite a big portion of my life making updates for people, since altogether i am in contact with 15 of the 16 siblings (and their families) my kids have, as well as DD2 and DS bmum, andd a fantastic former teacher of DD2's. So that's 19 people altogether (although a few of the siblings are adopted together).
However, I am actually in a dilemma about a few contact bits at the moment, can i pick you brains? The 16th sibling i am not in contact with... was adopted as a baby. I was hoping to have a letter or two year going back and forth with lots of pictures etc, maybe more if it was right for both DD1 and this sibling later to see each other etc. That is what i always have done with all the other families. I send letters, pictures, videos, and we are going to organise visits with a couple of DD2's sibs next year. But the family who adopted this sibling didn't want any contact whatsoever with any of the brothers and sisters, none of us has heard anything from them ever, except me once when i asked sw to ask them about contact, and they sent a short letter back through the sw that basically they didn't see any need for any contact and this sib had already had a perfect start with them and didn't need to live life with any reminders whatsoever that she had ever lived anywhere else etc. They said more and it sounded to me like they wanted to forget about adoption altogether and couldn't care less about any of the rest of us 
So for well over a decade, total blank about what this sibling is doing, anything about them at all. And i have dd's questions therefore - she is so hurt and wants to know all about her younger sib, adn waht she likes doing, and all that. So just yesterday I typed this siblings name into facebook, and there they were! They must have had a profile for a few years, given their age, but obviously has just lapsed all the security settings. I am absolutely sure this is them, for a couple of reasons. The problem is, that if i have found profile, then DD1 soon will as well, sice i know she types this sibs name into searchengines nd fb in hope...so what do i say to her? I doubt she is going to want to wait until this sib is 18, then go through all the proper channels. i wish she would, but i think she will just try and friend them if she sees them there. Which would open up a whole can of worms im sure we can deal with better in a years time, when DD can get counselling if she makes a proper reunion request. So i am in doggy doo doo right now, for want of a better word 
. Any advice?
On a positive note, i am organising festive season visits with tqwo of DD2's older sibs, who are lovely people, and they adore her, they like to spoil her rotten and they really care - tehy could listen to her chat about her life all day So we are all counting down to the visits now!