Yes, I'm sure HFT does care about posted size, but for me trading the ES, I can see its always far enough away from the inside bid/ask as to not get it, and it either disappears very quickly, or at least when price does get closer. The whole idea is just to push price one way or another.
What I also see is simultaneous huge size on the bid and ask, thereby cancelling eachother out. This is I presume to confuse whatever algos try and make sense of if there is more interest on one side.
There most certainly is. But once again, since this discussion is about stocks, and all my knowledge is about the ES/NQ, then I'm not sure how much of what I say applied. In general terms though, these days, there is no reason to post your intent to trade. If anything, what you want to do is push price into your order, and when it gets there, bam, you hit it. But whatever interesting things I see only work half the time, so its not like I've seen a holy grail in there anywhere.
