:) It's more like an initiative to help grow steemit and its memebers - it's a bit more serious than just selling things for your own personal gains. you can read about the core idea here:

https://steemit.com/steemfleamarket/@steemfleamarket/steem-flea-market-is-now-live-give-your-stuff-away-trade-buy-or-sell-and-earn-sbd-just-by-commenting