We all still use ours. It's not a great idea if you want to get on with work without being distracted but it was much easier getting to know people in the first few weeks with all the doors open.
We also have mini whiteboards on our bedroom doors, which we use to tell people where we are or just leave messages for each other.
We used to leave our doors open in our flat in first year so everyone knew we were in
I generally had my door open anyway as I liked my flatmates popping in to say hello every now and then.... but everyone's different! You'll set your own rules as a flat/house share and things will change as the year continues.
It is great just to be able to talk to others when your a bit bored. Definitely take a door stop and leave you door open when you are in over freshers week to get to know your flatmates and throughout the year to not miss out.
my floor did, but downstairs didn't because the only girl that was sociable and that we liked always came upstairs.
we used them all year as well, not just freshers week, because our doors automatically shut and locked so it was the easiest way to let people know we were in.
we used a traffic cone to keep our hallway door open (also automatically shut and locked), although when the accommodation office took it we used our hoover.