This is basically a buy from each other game.  You buy from the list of sellers and once you do, you post on the thread what you bought.  Then your name gets put on the list for people to buy from you too.  The more you buy, the more "hearts" you get.  When someone buys from you, you lose a heart.  Once all your hearts are gone, you're off the list.  So you have to keep buying from other people on the list the keep up your number of hearts.  Make sense?

I did one once and no one bought from me.  Just because you participate doesn't mean anyone will purchase back.  SO I didn't find it helpful.  But what I did find helpful was participating in something similar with the Sneak Attack team.  They do a game called the 20 Dollar Thingy.  Basically, one person starts the game by spending $20 in someone's shop (they get a list of people who want to participate and pick someone off the list).  That person then spends the $20 on someone else's shop, and so on.  So it's basically a trade thing, but every time you get shopped, you get to go shopping.  And then people post what they bought from one another.  So it gets your items out there a little more and gets your sales up.