Is this now acceptable neighbor behavior?

[CarlSpackler]

I'll preface this by saying these are my favorite neighbors and I have no problem with them or what they did. Now the behavior in question:

I live in a house in a middle class neighborhood. I'm pulling into my driveway after work the other day, and I notice an office chair placed on the curb in front of my neighbors' house. There is a piece of paper taped on said office chair, with the word 'FREE' written in black magic marker. I actually lol'd when I saw this.

When I leave for work the next morning, to my surprise, the office chair is gone. I'm like, "wow, someone actually picked that up and got themselves a free used office chair." That night as I'm leaving my house to go to the bar, of course I come across the remains of 1/2 of the office chair in the middle of the street a block up. While I'm no Sherlock Holmes, I suspect the skater kids who frequently roam the streets in front of my house, took the office chair, and had their fun with it.

So back to my original question. Is it now socially acceptable to leave unwanted items on the curb in front of your house, marking them as 'FREE' for anyone to take? For example, can I take the 10 year old computer tower and monitor that I have stuck in storage in my house, place them on the curb and mark them as free? I'm curious as to what others think.