From the the post, How Well Do You Actually Know The People You Friend On Facebook?:

EmilieEggleston -- I am one of those facebook resisters.  I think it's because facebook tempts me to add people I actually DON'T know very well, and later I feel guilty like a stalker. Unfriending is a hard decision because you have to request friendship AGAIN if you want to read their content, and that makes you look flakey.  Just unnecessary.

Of the close friends and family I keep in touch with on a daily basis, none of them bothered to use facebook much, so I saw no point in keeping my profile. We've been broken up since Feb 2011.

Now I happily use G+ to talk with others about my interests without having to request friendship. :)

Productive Web Apps  -  I need to do a facebook cull soon! No such problem with +Google+ and it's Circles!!! :-D

Laura Spencer  -  For Facebook, I'm very careful who I friend and don't friend. That's not so true on the other social networks, though. And, of course, this title could easily read: How Well Do You Actually Know the People Your Friend on Google+, Twitter, or any number of social platforms.

Nice reminder to be more careful.

 Крыстафер Гомес-  You don't really need to be careful as much as discerning.

Most people have trouble seeing marketing schemes - and those kinds of schemes use the same tactics as distasteful individuals.

To "know" everyone on your "Friend List" is nearly an unreasonable solution - if you only talked to people you "know", you'll never meet anyone new.

And sometimes those we think we "know" turn out to be entities we'd rather not.

And then sometimes the people we know well are the spreaders of digital plague.

So, just be wise about how you drive as much as wise about how you social-network.

From the thread on Google+: