Getting right to the point, some examples are: "alright", "alot", "eachother", and "ahold". My education has been nonstandard, but for the most part I use good grammar. I capitalize "I" and the first letter of sentences. I know what semicolons are for, though I seldom use them. I even know when it would be correct to write "cats'" and why you would never write "childrens'". And I hate txt spk as much as the next guy. But I'm convinced contractions like the above are an improvement on the standard form and keep using them even though I sometimes get criticized for it.

There, I did it!
It was more a rhetorical statement than anything. I just think structure and grammar-wise English is one of the easiest languages to learn. Verb conjugation is simple, word order logical- subject/verb/objects, no inflections like Latin or German.
And I think lovely things are written, sung and said in English. For 3.99? It's a steal! :)
And yeah, I know some of those words have more acceptance than others. "Alright" is accepted by pretty much everyone outside of very formal contexts, whereas on the other extreme "eachother" doesn't seem common.
And we have a few compound-words in English too. E.g.
"meaningless" "whatever" "whichever" "however" "whenever" "within" "anyway" "sometimes" "without" just to state a few, excluding words combined with a hyphen
"alright", "alot" - These are VERY common mistakes.
"ahold" - Not an error - http://grammar.quickanddirtytips.com/one-word-or-two.aspx
My personal favourites: "nevermind" "nowdays"
The cause for writing it wrong is because that's how it's often spoken, without a pause between the words.
Ah, you probably just guessed who's the new Grammar Nazi around here.