I've been online in one form or another since the early 1990's, and the expansion of the web, both as a useful tool and as a major time sink blows my mind. I played WoW, an online computer game for several years (I still log on to my account now and again but spend very little time playing anymore), and several years ago, one of my so-called "real-life" friends who also played WoW commented (in response to being passed over for his guild's "core" raid team because they already had enough shamans) that the internet was shaping up to be yet another tool that humans use to hurt each other's feelings.
This study, performed by a researcher at Penn State [http://live.psu.edu/story/58872] suggests my friend was right. According to this research, college students find online rejections just as distressing as face to face rejections. Although the investigators caution that their results may not apply equally to older demographics, I wouldn't be surprised if future research finds that us old fogeys can also be deeply hurt by things that happen on the web.
As a mature adult with FB friends who are (mostly) mature adults, I am at least spared the horrors of internet bullying, sexual harassment, or those awful pranks where a bunch of popular kids will friend, then promptly unfriend, an unpopular peer. But I definitely feel a genuine stab of pain when someone I know and think I have an amiable relationship with in RL ignores or rejects my friend request.
Even worse is when someone unfriends me with no (by my way of thinking) provocation or explanation. Since FB doesn't send special messages saying you've been unfriended, it can take me several days or weeks to notice that someone is no longer on my friends list but is still active on FB. This has happened to me (with a person I'm friendly with--I thought--in real life). It has, I'll freely admit, undermined my feelings towards this person. Every time I see her now, my smile is a little bit forced.
There are also those little hissy fits and small dramas that some people throw on social media of various kinds. In these cases, the people may not eventually unfriend one another, but if you get caught in the crossfire (by inadvertently posting a comment in a thread you didn't know was heating up because of something simmering below the surface), you almost wish they would. I really scratch my head when two people who do have a robust RL relationship use FB or twitter as a platform for, say, marital or familial quarrels or try to draw their friends (and more distant acquaintances) into the drama.
The thing is, there really isn't any good way to know if someone is hurt or angry by something that's said (or not said) in an online environment unless they choose to tell you. Yet communicating one's hurt or anger is almost guaranteed to engender hurt and anger (and possibly drama) in turn. Withdrawing is often the easiest way to deal with conflict in this setting.
I wish I had some words of wisdom on this issue that were more profound or unique than simply enjoining people to always keep in mind that there's a real person on the other end of every internet communication and to give people the benefit of the doubt rather than assuming they said something specifically to hurt you. Obviously, I don't want to force someone to be my FB buddy, critiquing partner or twitter followed if what I have to say bores or offends them. Logically, I know that no one is 100% popular and I know that even my nearest and dearest consider me quirky and off the wall in some ways. But emotionally, I want to be loved.
It's certainly true that humans, like other social animals, evolved in an environment where interactions were face to face and conflicts were resolved fairly quickly. Being a member of the pack, herd or clan was important to one's survival, so that stab of guilty shame and sadness one feels when rejected or rebuked is a neurological and endicrinological survival mechanism that's been shaped over millions of years. The development of language, writing and finally the internet has only expanded the opportunities for social embarrassment and rejection. I'm not convinced that our social conventions, let alone our hard wiring, have really caught up with what it means to be able to communicate instantly and remotely, let alone given us the tools we need to do so responsibly and compassionately--and to put these communications into an appropriate perspective.
But unless one wants to take the approach my husband has embraced (no social media and minimal e-mail communication), we'll have to muddle through and hope for the best.