You can tell by looking at how many are lining up at one price on the bid and the other price on the ask. The prices at the top are the current bid and ask. In your example it would be .0002 x .0003 9x5. There are mm's at .0001 in your example because it is the next bid price. So if there were a major sell off and that nine wall started to fall, the bid would eventually become the next price and in this case it would be .0001. For the price to go up you want to see good bid support which would mean more mm's at the bid than at the ask. The 50 represents the size - mm's usually show 5000 share on pennies - that example you gave is a very weird looking level II with ARCA having a larger offer than the other mms. Here are a few sites you can look into: http://www.investopedia.com/articles/trading/06/Level2Quotes.asp http://www.hotstockmarket.com/forums/showthread.php?t=35169
News 
Market Data 
Discover 
AI
