I must be drinking decaf today. (Stewart's generous explanation truncated to 
focus on a question):

> Well, technically, you are: if, for example, you send out five CDs, you'll 
> get back five CDs in return.  They're just not from the people you sent 
> your CDs out to!  And you won't get sent any more CDs until you send out 
> more.

> You're trading the discs, not selling them.  LaLa gets their $1.49 per 
> disc for paying postage, providing the envelopes and, most importantly, 
> putting you together with this person you've never met in Washington DC 
> who wants your copy of Kirsty MacColl's TITANIC DAYS *and* this person 
> you've never met in Chicago who's willing to send you her copy of the 
> Close Lobsters' FOXHEADS STALK THIS LAND.

> Your requests are more passive than that: you've got a want list on the 
> site that LaLa uses to let other users know that you want someone's Kirsty 
> MacColl CD.  If a person is willing to give up his Kirsty MacColl CD, he's 
> the one who initiates the transaction.  You only know that you're getting 
> the disc when someone agrees to ship it.

So all things being even, your disc plus $1.49 equals a disc from your want 
list. Sounds fair - used CDs are usually $5 or more in stores, plus tax, and 
although I've never sold a used CD I understand the $$ you get is pitiful. 
I'm okay on that part.

But...

So I'm that Kirsty MacCall owner and I agree to send that disc to person #1, 
and I also agree to send a Zappa cd to user #2. I'm guaranteed that I will 
get two items from my want list sent to me (albeit probably from completely 
different people) in return? Since senders initiate the transaction, how 
does that get driven and balanced?

Just not understanding how they even out what you send with what you 
get...there's got to be people who are always up a couple/few discs and 
others who have been sending more than they receive. Based upon your first 
paragraph, if you're "in the red", is your list off limits as a source until 
you acquire a couple of discs to even up?

By the time we're done here, Stewart, we can sell (err....trade) this to 
LaLa as a FAQ file. :)

cheers
b