Don't forget about shortening words and using acronyms to make tweets fit!
Each tweet on Twitter only allows 140 characters which run out pretty fast. So everyone has to make it fit but making words shorter if they can. It's so common for people to write "B" instead of "be" or "2" instead of "to." There is a limitless number of these, and there are no rules. It just has to make sense!
Some others I can think of are "pls" for "please," "ur" instead of "you are," "n" instead of "and" and so forth.
There are even "Twitter recipes" which feature an entire recipe fit into 140 characters! With lots of shortened words of course!