Yes exactly! Its an exchange of fics. You won't write for the same person who wrote for you, but you will both receive and write a fic.

There is an option to become a "pinch hit" participant. These are writers who don't make a commitment to the exchange, (though they can be a normal participant) but will be able to write a work in a small time frame for a participant if there are any drop outs. These may write a fic and not receive one specific to them.

There's no option to receive a gift without writing one as well. That's what a normal fest is for~