Seventh letter of THE GREEK ALPHABET.
If you perceive it as lame, I will not make an issue of that. It is not, specifically, superfluous. There is a character limit on the amount of text that can be entered in the “reason for edit” box, while one may enter as much text as one can type in five minutes (allowing for server speed) following “ETA.”
One could argue that a second post is adequate, but then one risks having one’s thoughts interrupted by the seventeen paragraph response from some more loquacious poster who hit submit 3/10 of a second after your initial post, so there are reasons to use ETA even if you find them lame.
Why make up a new TLA when we have a perfectly serviceable abreviation already that’s been in use for centuries and that everyone is familiar with?
P.S. When I see “ETA” I think of potato chips.
tomndebb, I find your post to be nothing but ETA apologia that does not address my point at all. 
Limitations on the “reason” field would never be touched by a simple explanation like “added the last three paragraphs.”
If a post was so incoherent that it required microsurgery, then “ETA” wouldn’t help it either.
Verdict on appeal: Still lame.
{never mind}
But thanks, someone, for pointing out the “Reason” field. I knew it was there somewhere, but couldn’t find it in earlier edits.
You bastard! How dare you toy with the emotions of a hungry man!