I hardly ever log in to my facebook account. It's not really my cup of tea. Nonetheless, I can somewhat relate to your experience in that at one time I had a good friend online who stopped emailing me and then popped in out of the blue to comment on something I had posted on my website. It turns out this person had begun following my website and that apparently met their needs and they felt no need to actually engage me in conversation. This was kind of an icky moment for me. The friendship later ended.

I continue to wrestle with my relationship to such things. You can only have so many actual close friends. There are only so many hours in the day and close friendship requires sustained, on-going interaction to maintain. For this reason, I tend to think "social networks" are doomed to be shallow affairs. Yet, paradoxically, I find that I share a lot more info online than I do with most folks I know in person. I'm not shy there just isn't enough time in the day to explain some things to everyone I meet, so I just don't want to open up some can of worms. Still, I wrestle with this process where I seem to gradually be working on developing an online audience where the relationship is inherently lopsided: Other people often know a great deal more about me than I know about them. But this isn't really what I think of as friendship and I like having friends, which have been a tad scarce of late (remaking your life usually causes you to shed friends).

I don't have answers for you. Just sharing some of my own internal questions, FWIW.