It's something that has been bothering me for AGES. It kills my eyes on Facebook, Twitter, blog posts, and other websites when I see people not writing properly and using the so-called "text-talk". Of course it doesn't take a genius to figure out what the author of the post intended to say, but it still takes time to read, and most importantly, time to write too. So now that I've got your attention, why don't you have a seat and read this post as I will only post it once and don't have all day to explain.

O, Y, R, U, and C are LETTERS and not words. It kills everyones' eyes to see these on any message. Besides, it doesn't cost you anything to type in two extra letters to make a properly spelled word. This not only goes for the letters, but for shortened words of short words, such as "ur". USE IT RIGHT.
O=oh
Y=why
R=are
U=you
C=see
Ur=your, you're, you are. See note below.

AlSo WhAt i$ tEh p0INt oF TYPING lieK dis? Please, type normally. You wouldn't write a college app like that. Complete waste of time to type, probably also messes up your shift key, and also messes up yours and other peoples' brains. It strains my eyes.

This leads me to a point of also writing TH instead of D, like instead of "Dis", write "this". Also goes for "dat", "dem", "dose" and what not. You sound like a ten year old when you type like that. Even Soulja Boy is smart enough to write "Crank That" for the iTunes release, but not smart enough to write "soulja" instead of "soldier" or "soul" or whatever the hell he meant.

Another point I'd like to make is replacing normal letters with capital ones or numbers or other characters. Trust me, sounding ghetto on a post is not cool and all it does is further prove how illiterate you are. Oh, and moving letters around too, as in "teh" on purpose in every appearance. Sure, I understand that you could do a typo, but maximum that can occur is once. Even with that, your browser should underline that word and tell you that it's spelled wrong. But when that is used for every instance, it drives any normal person nuts.

And please, keep 4chan language and stuff on 4chan and nowhere else. I'm not going to even get into the details of that.

CAPS LOCK ALSO MAKES IT LOOK LIKE YOU'RE SHOUTING AT ME. ALTHOUGH IT IS A USEFUL TOOL TO ANNOY SOMEONE, DO MIND IT IS QUITE RUDE TO DO SO. A POWERFUL WEAPON, CAPS LOCK SHOULD BE ONLY USED IN VERY RARE CASES WHERE NO OTHER WAY OF EXPLANATION IS POSSIBLE.
Also, I Don't Get The Point Of Capitalizing Every Word In The Sentence.

Now that I have covered the easy stuff, let us immerse ourselves into the more complicated aspects of the English language- grammar. I know, grammar is a bitch and it is boring at school, but these are some of the rules that may not be broken at any costs (actually, all rules shouldn't be broken, but there are too many of them to be listed in a single blog post, so if you know them, good for you).

APOSTROPHES
Here is an apostrophe: '
Now you probably know where to put one; to combine two words together, contractions, and what-not. However, you have to use the correctly. Here are the commonly misused situations:
1. Its a beautiful day.
The wrong form of its/it's is used. The proper form is "it's" because the sentence is telling that "it is a beautiful day", and the contracted form combines the words "it" and "is". Therefore, the correct way would be, "It's a beautiful day."
2. The dog is in it's house.
Now this is a mistake that makes me rage. This is one of the worst mistakes to make in the language. The it's in the sentence there is a contraction of "it" and "is", and if we plug that in instead of the contraction, we would get a sentence that doesn't make sense- "the dog is in it is house." So, the proper form would be "its" as it is the possessive form. This form usually comes before the noun (object) and after the main clause (main noun (object) and main verb (action)). Therefore, the right way to write that sentence would be "the dog is in its house."

Now onto the your/you're/you are...
Let's take pop culture as an example:
3. Your a jerk
This form of "your" is possessive. That is, for possessions, as in "your wallet" or "your dog". The correct way to write it is "you're a jerk" OR "you are a jerk". The reason being is that "you're" and "you are" have the exact same meaning, but are just written differently. This is the directional form, and is addressed to someone or something.
4. I am going to you're house.
As explained above, this form is the directional and is used to address someone or something. The form that needs to be used in this sentence is the possessive form as the house is someone's possession. So, proper way is "I am going to your house."

Another commonly misused word group is the there/their/they're.
5. Their are ten cars.
This sentence is wrong because the wrong form is used. This their is the possessive form and is used to address the possessions. The right form is "there", because this form explains the situation in the sentence. The correct way of writing this is "There are ten cars."
6. I'm in there car.
The sentence is wrong because it is using the wrong form of there (obviously). The correct form for this instance is "their" as it is the possessive form and car is a possession. So, the correct sentence is "I'm in their car."
7. There very loud.
Again, wrong form used here. The correct form should be the form that addresses someone/something- "they're". So, the correct form is "They're very loud."

COMMAS
This is a comma: ,
It is used to separate words. There are about fifteen rules, according to the OWL from Purdue.
1. Separate independent clauses.
2. Separate introductory phrases, clauses, or words before the main clause.
3. To set off clauses that are not essential to the meaning of the sentence.
4. Separate THREE or more words, phrases, or clauses in a series (list).
5. Separate two or more coordinate adjectives that describe the same noun.
6. Near the end of a sentence to separate contrasted coordinate elements or to indicate a distinct pause or shift.
7. To set off phrases at the end of the sentence that refer back to the beginning or middle of the sentence.
8. To shift between the main discourse and a quotation.
9. To avoid confusion.
There are more rules on the Purdue site, and a simple Google search should give it to you.