What I am noticing is that correspondence seems to get lost in the trash heap that we call "The Wall". Many people see so many peoples' postings (many are about mundane things such as likes, photo updates and whos friending who) that they skim over everything. Unfortunately, the baby gets thrown out with the bathwater. The few posts with substance are missed.
I sadly had this happen last week, when I sent a friend birthday greetings. I also told him that I would like to talk to him on the phone sometime. I am thinking that he just didn't see the message.
I am also noticing that people are using Facebook less to actually disclose what is going on in their actual lives. I am not sure where people are turning, but it seems that more people are using blogs and Twitter to talk about their lives and get their point across.
Also, certain mobile applications of Facebook will not allow people to see private messages on their phone, so the the private messages get lost.
Lastly, and I know that this is a tough one for people with AS, but when you get out and live life, you seem to attract more posts to Facebook. I am surprised the number of posts that I have got that said " it was nice to visit with you today", "here is the answer to the question that you asked", "it was nice to see you", etc. Sometimes living a full life will cause you to be noticed more on Facebook as well.