h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The first one is the best documented: a humorous article on March 23, 1839, in the Boston Morning Post, with o. k. used and immediately explained as standing for 'all correct'.

"There was a fashion then for playful abbreviations like i.s.b.d (it shall be done), r.t.b.s (remains to be seen), and s.p. (small potatoes). They were the early ancestors of OMG, LOL, and tl;dr. A twist on the trend was to base the abbreviations on alternate spellings or misspellings, so "no go" was k.g. (know go) and "all right" was o.w. (oll write). So it wasn't so surprising for someone come up with o.k. for oll korrect."

http://www.yahoo.com/news/where-did-expression-ok-come-083000677.html?ref=gs

In postal codes in the U.S., OK is the abbreviation for Oklahoma.

The Greek derivation for 'ok' from TC's link is also persuasive.

A number of those etymological suggestions have a grain of substance to them.

Maybe its the convergence that accounts for acceptance of the term.

Omar Khayyam's initials are O.K.

Yeah, they're not bad.

His poetry isn't bad either. In fact, it's OK.

when I was in the army and communicating live with someone via telex we always used abbreviations/TLAs because it saved time and often the person at the other end couldn't type properly.

and for security and speed a lot of Q codes. I miss those days.

Why? Are they missing?

[sorry, couldn't resist ]