Some of these mistakes have become so common, they are not used more than the correct phrase. For instance in UK English (I'm not entirely sure about US English), there is no alright, the word is always all right. But you wouldn't know this from looking at how the word is usually written!
Welcome to the Community of Concern, Liz. And thanks your comment. Mr. Rewrite loses a great deal of sleep over slippage in U.S. English. The motto here seems to be: "Use it incorrectly enough and it'll wind up in the dictionary!"
Maybe if enough people misspell Mr. Rewrite's real name (Elliot, Eliot or Eliott rather than the correct Elliott – a frequent occurrence) the powers that be will rename him El(l)iot(t). Then everyone's covered and we in the U.S. can get back to debating the existence of gravity.
Mr. Rewrite's Webster's New World Dictionary has an entry for alright, but it's only to note the shorter form as a "disputed variant of all right." If his dictionary had a Facebook "Like" button next to that entry, Mr. Rewrite would click it.
Dictionary.com, which seems willing to validate pretty much any way someone wants to spell a word, allows alright. It adds a usage note saying that alright probably stems from people identifying with already and altogether. Its recommendation: alright is all right in informal contexts; all right is appropriate for formal writing. Please allow Mr. Rewrite a moment to scare Mrs. Rewrite and Rewrite Jr. with a primal scream.
Here's a reason to worry, Liz: Garner's Modern American Usage (cue angelic chorus), which frowns upon alright, suggests that the shortened form is gaining more traction ("a shadowy acceptance," he writes) in British English. Garner continues: "[T]he combined version cannot yet be considered standard – or even colloquially all right." Get it? Bryan A. Garner is Mr. Rewrite's hero.
Mr. Rewrite is bound by The Associated Press Stylebook, which is refreshingly terse on the matter: "Never alright." His very expensive Chicago Manual of Style, which governs many others, is similarly brief: "Two words. Avoid alright."
Perhaps the best take comes from Fowler's Modern English Usage: "The use of all right, or the inability to see that there is anything wrong with alright, reveals one's background, upbringing, education, etc., perhaps as much as any word in the language."
Even worse: It will out you as a Dictionary.com user.
In other news, The (Tacoma, Wash.) News Tribune offers readers this mea culpa for and explanation of errors in headlines, stories, etc., etc. Noting that the newspaper has had to cut back on copy editor positions, the executive editor outlines steps for improving quality.