Please stop accusing me of having some sort of hidden agenda. I can't recall when the last time I even mentioned level 2 on these boards was so to say I'm using "jargon" to try and convince people to use something is just insanely stupid.
Level II is a pay-for service for daytraders or investors or anyone else who may want to see the depth of orders and the depth of bids and asks as posted by Market Makers.
One can view which MM is offering what and which is bidding what and you can view the size of thier orders as well. This gives a trader a view of both demand and supply of shares and allows him/her to trade accordingly.
If you are not using Level II and you are trading... you are going at it literally quite blind .. You are bound to lose money if you daytrade and do not use LII
Mommo traders sometimes do not use it as the nature of high momentum would not always require that you need it .. but I would.
A COUPLE OF SECONDS can mean the difference of a COUPLE of THOUSAND dollars.... Mim has sage advice and you really should consider it rather than dismissing it out of hand. .. many ppl here will try to deceive you... but I have been lurking and while he and I have different trading styles, he is trying to help you to understand ... while you are on the sidelines, I invite you to peruse other boards and read ALOT .. you will find there are good and genuine traders here from whom you can learn .. Good luck
Market Data 
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