de-friend, un-follow.

i'm wondering what proper etiquette is for the social networking world i.e. blogger and facebook and twitter. i'm not, nor have i ever been one who is desperate for friends on public websites and in the past i think i may have come off as a little cruel with my social networking habits.
i originally got on to facebook to get away from the trashy myspace world (seriously. does anyone even have myspace anymore?) and to connect with those that i had lost touch with over the years. i started out by adding people that i knew and that i knew i'd want to stay in touch with. from there, i began getting requests and that's where it all got foggy and turned into a popularity contest. people that i knew in high school, but never really spoke to, began adding me and i would always debate with myself whether or not i should accept them as facebook friends. i know, it sounds mean, but my reasoning was i didn't really talk to them in high school (and vice versa) am i going to talk to them now? probably not.
then i devised a system. i'd accept the friend request (only if i knew them. i never accepted a friend request of someone i didn't know) and if we hadn't spoken to each other in the first week that we were friends, i'd de-friend them. that is the system i still work by today. that sounds even more mean, to de-friend someone, but i just don't understand the need to be facebook friends with someone if i'm not or was never friends with them in "real life". its more a privacy issue than a mean girls type of thing. if i'm not going to talk to someone and if they're not going to talk to me, why do they need to know my business? in my opinion, they don't. adding people just to see the number of friends you have increase is pretty shallow and it reminds me too much of what myspace (and high school) was like. in addition to that, every 6 months or so i'll go through my friends list and de-friend people i haven't spoken to in quite some time. is this mean? am i crossing some invisible jerk-border that exists in the facebook world? i'm not sure that i'll change my ways, but i am curious: when is it okay (if ever) to de-friend someone?
with that in mind, lets talk about blogs for a mintue. i'll be the first person to admit that there are a few blogs out there that i started following because it was a give away requirement. but they are few and far between. i mean really few and far between. the other blogs i follow, i actually read their posts and enjoy what i read. if i'm commenting, i'm there because i like what was written. but while going through my blog list tonight, i came across a few blogs that i just don't read anymore. not because they aren't great blogs but just because i don't find myself taking the time to read them anymore. at that point, i wonder if its okay for me to no longer follow them. i mean out of the 90+ [awesome] followers i have, i wonder how many of them actually read my blog. and if those that no longer read my blog stopped following me, how many followers would i really have? (just a curiosity i have. . .)
where followers in the blog/twitter world are kind of a big deal (it shows you aren't just talking to yourself), it seems un-following a blog would be treading on egg shells. but perhaps i'm over thinking it? i know when i loose followers i wonder if i said something offensive or if i change my blog design too much, and then i get over it. so, if it doesn't bother me that much, how much does it bother other bloggers? i mean, you have to wonder what exactly it was that made that person un-follow your blog, right? but in the long run, does it matter? so, when is it okay (again, if ever) to un-follow a blog, or a twitter?

what're your thoughts on the matter?