If your tracking opponents hands, then you should be able to see the number of hands they play from each position at the table.
If over a large sample size, you see that a player is playing the same number of hands from any position then they probably are not positionally aware.
If over a large sample size, you see that a player is playing the an increasing number of hands as their position gets closer to the button, then they are probably positionally aware.
A positionally unaware player will open a hand like A6 no matter the position whereas a positionally aware may only open it from the CU/BTN.
You can exploit an unaware player by playing more pots with them when you have position on them.
i guess i'll kick it off..playing in position is a really important part of poker - the terms positionally aware and unaware refer to a players awareness of this fact.
playing out of position means that you are first to act which immediately puts you at a disadvantage, as your opponents are able to see your action first and respond accordingly. playing too many hands from out of position means that an aware opponent is able to exploit you, as your range will be too wide to connect with a lot of boards.
(a pretty crude definition of exploiting is: to consider a person's range and bluff/call accordingly - ie if their range is too wide, bluff/call; if it is really tight, fold)
hope this helps.