OP: original post (usually meaning the first post in the thread) or original poster (meaning the person who started the thread)
ETA: edited to add
nm: never mind. Used when someone re-thought a post and decided not to say what had originally been written. You can’t just delete your posts entirely and there’s only a five-minute window, so sometimes the best thing is to replace your words with never mind or nm and move on.
Thanks a lot. nm really had me vexed.
I would be honored to be your internet translator! FFR (for future reference):
OP means either Original Post, the first post in the thread, or (remember my conjunction lesson about agreement) Original Poster, the person who wrote it. I try to keep them clear, but some people don’t and you are left wondering if the user is complaining about the post or the poster and can lead to hurt feelings. You might have noticed that I usually place a comma before a conjunction but not always. This can depend on how independent I feel the following clause is, or just my mood.
Commas, semicolons, and parentheses are punctuation I use to excess because I seem to be allergic to periods/full stops. Back when the Bulwer Lytton contest was a serious investigation into endless sentences and the abuse of the English language, I was tempted to submit one of mine that had simply ended up that way.
As it is, I have written sentences containing more semicolons than the average American uses in his life. This is because I write to be read aloud, like Bulwer Lytton did, because that’s how I read it. Try it and treat my commas as quarter rests, semicolons as half rests, and periods as full rests. There can be method to my madness, sometimes.
And ninjaed by **Dewey Finn **means I took too long writing my reply.
Just use ellipsis sparingly…and you will be fine.
So, when I see a period in your writing, I should log off and get a good eight hours of sleep? 
When I was reading textbooks for Recording for the Blind I grew to love commas. The readings were always cold and done by a team of two, one outside the booth running the reel-to-reel recorder with hir own copy of the text, and the one inside the booth who only had to worry about reading the text.
Since it’s the first time either member has clapped eyes on the text, the reader is constantly darting forward a sentence or to to get an idea where the thread of the paragraph is going to get the right tone. When I was reading it was amazing how some writers could lay out the text so reading it was a joy and others were forcing you to constantly stop and redo a sentence because you had the wrong empthasis in it.
Commas were a big help and as a consequence, I put a lot of them in my writing, especially fiction. The professor in the English Comp class I took concurred, saying it worked for my style of writing.