Sam: bids, asks & sizesYou should be aware that market depth indicators are not very reliable, especially on certain markets.
If you're reading Nasdaq level II, for example, many of the bids and offers don't show up on otcbb stocks or if they are fractional-penny orders.
You've probably seen trades execute at something like $1.4199 or .8502.
This is the way traders jump the queue by edging under the low ask, or just over the high bid.
NASDAQ has changed the rules and is instructing ECN's and online brokers not to accept fractional-penny orders on some markets, and for any stocks over $1. The hitch is that some brokers and ECN's are still routing such orders, giving a few traders an unfair advantage.
There's nothing fair or level about this playing field, but it's changing.
So keep in mind that there may be a lot more size available near the bid/ask than shows up on market depth.
Gabriel