Ours doesn't require you Offer in order to Want... that'd be TRADING, not GIVING and they make a point of saying so.
But you can only post 3 Wanteds per month... and that's each item more or less, Mod's choice.
Like if you Wanted Christmas gifts you could say
Wanted: Kids Clothing... and inside the post... Size 6 Clothing For Boy, Size 8 Clothing for Girl
Wanted: Barbies (for the 8yo girl)
Wanted: Hot Wheels (for 6yo boy)
Those could be three separate Wanted posts, OR you could make it all in one and call it Christmas Gifts.
But, the actual things would be no more than three.
They sometimes allow a little wiggle room on the clothes, like if you have two kids... or said clothes and shoes... but I haven't really tracked it so that might just be the only two items they asked for that month. *shrug*
You couldn't make one that said Wanted: Christmas Gifts
Girls Clothing Size 8
Boys Clothing Size 6
Barbies
Hot Wheels
Princess TV and DVD Player
Cars TV and DVD Player
Girls Movies
Boys Movies
If you wanted all that you'd have to start in October and list three at a time... but again, ALL posts in our Yahoo Group Freecycle are approved by Mods before they're posted. If yours doesn't have that then it could be manipulated.
Once an Offer has been picked up then the person can post a TAKEN so others don't bug them, but it's not required so that can be annoying. There isn't any way (I know of?) where you can say GOTTEN after you've posted a Wanted... that'd be nice. Contact wise... the Offers and whatnot are posted on the Group Site/Emailed... but they don't really contain contact info (except the Offers that say it's on the curb first one here gets it) you have to click REPLY and whatever you write is sent to that person's email... then they can choose to reply, there's no limit on the number of people who can answer your Wanted or your Offer, so making sure you put in a Taken is the sane thing to do.