the logic of what ends up on flash sites can be baffling, but this I think makes sense.
1) 2006 was originally hailed as a great white vintage, but over last few years it's aura has dimmed, as some find it pushing overripeness and aging quickly (I like lots of 2006s, but not putting any for LT aging)
2) A string of vintages with pretty decent reps has followed
3) so if you are on wholesale/distributor level have a bunch of 2006 Montrachet that isn't selling, these are your choices
a) discount to usual retailers. Seems obvious, but there you have (I) an implication that your wines are overpriced, and that puts downward pressure on your more current (and future ) vintages and (II) a possibility that those retailers will pursue you for refunds on previously purchased bottles
b) discount to a flash site. No clawback, and a good chance that vast majority of customers are not regular Montrachet buyers and therefore no downward pressure on the vintage that is just released.
3-a-I is a scary possibility (witness the famed distributor dump when someone switches agencies, it's done for a reason - to send a message)