If you're talking about how to tell...
CO 12 HNL 20:50 LAX 05:00 +1 767 0 J9 D9 Z9 Y9 H9 K9 N9 B9 O9 V9 U9 Q9 I9 S9 W9 T9
AA 298 HNL 21:10 LAX 05:19 +1 757 0 F0 A0 Y6 B6 H0 M0 K0 L0 V0 G0 N0 W0 Q0 S0 O0

Well CO means Continental, AA means American, obviously.
then comes the flight number, with city information and depart/arrival times, then +1 means arriving the next day.
Then 767 or 757 is the aircraft type (Boeing 767 or 757).
Now the good stuff!
Each letter is a fare class (price range at which seats are sold) and the number indicates seat availability. For example, H0 means there are no seats left in the H fare class. While each airline has slight variations on fare classes (which you can find via some website-I'm sure someone will link), F and A are usually First Class and J might be business class. Some fare classes are unrestricted (full-fare, no discount) while others are the promotional cheap fares and others indicate government, award ticket, or non-revenue, etc.
So the AA flight has most seats gone while the CO flight still has many open seats.