I see this in conjunction with the fact that the volume for the YM has surged recently. For technical analysis, volume of the ER2 is irrelevant and misleading, since it is a "slave instrument", you should consider volumes of the NQ + ES ( + YM) instead.
The primary market is the S&P 500. There is the volume. The quotes for INDU / YM or the ER2 move of course in accordance to the SP first (see arb software) with minor divergences. (see Intra-Commodity Spreads, where one is long ES / short ER2 if the ES should perform better)
I have also heard that alot of prop futures guys are migrating to the ER2 of late. I would argue that this is a larger and larger percentage of the overall volume.
Yeah, I've seen some chatroom buddys trade the ER2 or the YM recently. The reason is that in the ES it is more&more difficult to get filled when joining bids&asks due to massive book size and the "large" tick size. However, I would not like the ES tick size to be reduced. I stick to the ES and IMO everything is fine !
Volume on YM and ER2 cannot be used for t/a purposes, only ES and NQ have enough volume to actually clue in on capitulation of moves etc. However, the idea of trading the ER2 is interesting.. I put it on my screen and will start following it today, see if it's tradeable.. seems more volatile than the others.