Teaching the internet

Simple lesson for today:
Your - belonging to you.
You're- you are
there- not here
their- belonging to them
they're- they are
u- a letter of the goddamn alphabet, not, as you may think "you"
r- another letter of the alphabet, you learned this in first grade. it is not "are"
grrl- I'm pretty sure I saw this in an episode of the live action Batman series. Pow, zap, grrl. It's not "girl" though.
boi- I don't know what you think this is, but it isn't "boy". No. No it isn't.