It's common practice where I am too, in the US, and where DD1 lives in the US too.
We have alleys and people leave out lots of things they no longer need, and others pick it all up. I found a bedframe complete with all its lathes - needed cleaning but great - a lovely book of Georgia O'Keeffe prints, two deck chairs that need new fabric but are otherwise fantastic, a plastic chest of drawers that I use for my sewing stuff, and an area rug. I was too late for a great sofa that I spotted. Currently I am on the lookout for an office/ swivel chair. When the weather starts to get nicer people will start to put items out and I will drive up and down alleys to scout.
Little Tykes toys disappear within minutes of being left out.
DD1 has found armchairs, and also a very nice suitcase with no stains, rips or mysterious smells.
You can leave out items with a lot of metal in them and the scrap metal man comes by in his little well-sprung truck and hauls them away - I left out my old sleeper couch springs and they tossed it up on top of the truck. They also removed a huge old dinosaur of a fridge from the basement of my old house (left behind by previous owners), and numerous other old metal items. People put out old stoves and washing machines, etc.
Often if people are remodelling and have a skip outside on the street in front, people come just after dark and climb in to rummage around and take stuff like old kitchen cabinets, pipes, doors and doorknobs, light fixtures, etc.
There are little free book boxes outside many residents' houses too. You can take what you want and leave off whatever books you want to dump.
When my DCs were young my friends and I used to bring bags of clothing around to each others' houses to have swaps. We got recycled jackets, snow bibs, snow boots, swimming togs and lots more and returned the favour.
Both DD1 and I live in pretty well heeled areas.