Having your mistake corrected can be educational even when you were understood. In the future, inanother context, the same mistake could result in confusion.
Well since we're all being pedantic, OP means "Original Poster" which is the person who started the thread (page, not this particular thread, which you did start).
I think that the meaning of OP depends on context. In general, you're correct. But cel1ne can be reasonably be referred to as the OP in our convo, since our discussion really doesn't have anything to do with the content submitted by the Original Poster of the whole page.
Having your mistake corrected can be educational even when you were understood. In the future, inanother context, the same mistake could result in confusion.