Like the internet itself, there is a lot of potential for good as well as bad here. I joined the site as a graduate student at Clemson back in 2004 when it was restricted to the college campus. Since then, I have accumulated roughly 440 "friends." How many of them do I talk to with any regularity? Maybe 50. Still, I like to keep tabs on people and see what some of my old friends and acquaintances are doing now. As for the good that has come out of this, I can think of several things. I have gotten in touch with a few people that I had really hoped to find. I rekindled a friendship with a high school buddy that I had not seen in more than 6 years and recently found an old running buddy that I had not seen since '98. He has since become a Christian and is inspired by my messages. I have joined and contributed to several health groups as well. I also used facebook to help organize an annual reunion with my old high school cross-country team. Lastly, I found a girl who had stuck up for me when I was being bullied but had not seen since 9th grade. When I messaged her to say thanks, she said that it affected her so much that she started crying. It turns out that she is a runner now as well and we've talked about doing a race together.
Now, the potential for bad:
First, posts are widely read and the social network can be used as a tool for cyber bullying as well as to betray trust, spread gossip and to slander other people. For this reason, I would restrict it to those 18 and older. If a teenager insists on joining, I would suggest that his/her parents set up a facebook of their own and insist on being "friends" as a condition for allowing them to have their page. That way, the parents can view everything that their kids post and can take action in the event of anything offensive or inappropriate.
Second, in order to be facebook friends, you have to send a request to add the person as a friend. The requested friend then has the power to accept, reject or leave you hanging. You can also remove a person from your list, which is known as "unfriend" or "de-friending" as I prefer to call it. This can potentially cause hurt feelings.
I generally have a policy of no rejections and no de-friending because I don't like it when it happens to me. I may make exceptions if I get a request from somebody who is obviously not a real person or if I have a bad break up/nasty falling out with a real life friend, I would de-friend. That has not happened yet. The downside to this is that I have people on my list that I really do not care to have. I was prepared to ask someone: "We haven't seen each other in 10 years and didn't like each other in high school. Why did you add me?" I ended up just accepting them and forgetting about it. I've also gotten requests from people that I am quite sure that I have never met before. I go ahead and accept them as well because they might click on my site and either hear the Gospel or get in better health.
Have I ever been rejected or de-friended? Yes. If it's a high school or college acquaintance that I never really liked in the first place, I don't care but I've had a couple times in which I was hurt a bit. I can understand dropping someone if they post insults about you or use the news feed to push their fringe political ideology. I may post a Scripture verse, race result or random thought on occasion but I'm not a news feed hog. I almost never air my political views but do identify myself as "conservative" on my profile and yes, I was once de-friended just for that. Some people, like my sister, choose to limit their friends to those in which they are extremely close and family members. I suppose that I can respect that. However, there have also been times that I see a former classmate that I liked with 40+ mutual friends and is obviously not too choosy yet I was not good enough to make the cut. That's pretty low. I was once de-friended by a co-worker who had always been very nice to my face. In another case, I was de-friended for no reason by someone who had recently thanked me "from the bottom of her heart" for praying for her and encouraging her. To me, that says "I don't care about you at all."
Facebook can be an effective networking tool and can help you gain or deepen friendships that you may not otherwise have. In some cases, an old acquaintance may embrace a cause that is very important to you or share a common interest later in life. Beginning runners have asked me for advice on Facebook. Perhaps most significantly, a college acquaintance developed adrenal fatigue so I mentioned my site and we ended up talking on the phone for a half hour. We were cordial back in college but I never really thought of her as a friend, that is not until recently. That's the best example of why I don't de-friend and readily accept others. In conclusion, I still think the good outweighs the bad so if any readers want to look up the one and only Justin Zehnder, go ahead and add me. You will not be rejected.