I used to use them a lot, mainly to give away items but for the odd ask (satelite mount) and we got a cover for our hottub when someone was throwing their old tub away (missed getting a back up pump though

). I used the site to give away most everything that came out of our basement reno (yes, people do actually want the 1980s light fixture, go figure) and met a neighbour down the street that way who has our old bathroom and kitchen cabinets in his laundry room now.
A great way to get rid of baby gear (if I couldn't find someone I knew who needed it) or toys the kids outgrew.
I stopped looking at our local site when it became a regular occurence for people to ask for food, diapers, grocery gift cards, rather than what I thought the purpose of the site was for - finding an alternative to throwing items out. For instance the woman who asked for paintballs gear for her boyfriend since he loved to paintball followed by a post from her asking for food and diapers for her children. Ummmm, where does he get money to paintball?
So now I am on a first name basis with the Goodwill drop-off point (uber convenient drive through location) and for larger items Habitat for Humanity will pick up. I love their ReStore, it's a great place to pick up furniture, just enough tile for a small job, etc. My friend who had to buy a place last year furnished the whole thing from the ReStore - she looked for good strong pieces and just painted them all black. Voila, matching furniture.
If you have good mods on your local Freecycle spot it can be a great community space. A bit addicting!