(piano music)

[Narrator] Mr. Know-it-all.

(upbeat music)

[Narrator] When is it OK to unfriend people

on Facebook you don't want to know any more?

When you first got on Facebook,

you probably friended a bunch of people

you hadn't seen since high school.

That was foolish

because now you want to extricate yourself,

kind of like high school graduation all over again.

Perhaps the greatest theorist of friendship

was 18th century man of letters, Dr. Samuel Johnson.

He wrote widely on the topic

and, for some reason,

also quite a bit about his gout.

Johnson claimed he never forced himself

to read a bad book all the way through.

So, why not similarly quit second-rate friends?

Social networks have since reworked

the definition of a friend

to include people like estranged classmates

who used to throw pine cones at me,

I mean, you.

(plonk)

But this isn't like feeling guilty

about giving up halfway through

some great piece of literature.

These former associations are more like

the entirely unread copy

of that bestselling teen vampire saga

your aunt got you five years ago.

Expel them as mobs of pitchfork-wielding townsfolk

would expel shiny, shirtless, soccer-playing vampires

or whatever those books are about.

(biting)

I'm Mr. Know-it-all

which means I already know

whether or not you are interested in

clicking on the subscribe button.

You are.

(upbeat music)