<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by dogcanyon:
If you use http://flyaow.com/class.htm you will see that their availability by class often fluctuates wildly within a matter of several minutes or hours </font>
I attribute a sudden drop of available seats to 0 as due to loss of connectivity to the booking system seat availability database. And the return to the real level is seen when that connection is re-established ... in other words, these are defects in the web software implementation and not real changes.
The recent downtime when BA converted to Amadeus demonstrated this and serves as confirmation (at least to my satisfaction). I'm fairly sure that there is no yield management going on with such frequent changes. You need considerable talent to infer the actual flight state (bookings) from the publicly-available information.