[Tagging] Tradeoff

[Tobias]

> Tradeoff sounds too unspecific to me. amenity=public_bookcase is used once
> already.

I was quiet unsure of the usage of the word tradeoff. I hope that there
is a similar word which describes a place where you can leave 2nd hand
things and it is offered to pick them up for free. In this context I
also know a place where you can leave everything.

So in this context amenity=public_bookcase is quite non-generic.

Just assume tradeoff is the right phrase. I propose something like

amenity=tradeoff
tradeoff=public_bookcase

> Anyway, they are usually tagged as amenity=library, because that's what they essentially are. 

Sometimes they are called library e.g. Vertrauens Bibliothek.

http://www.openstreetmap.org/browse/node/2359237222

But in this case it is possibly intended that people put a book and pick
another up - which is not necessary for a public bookcase. But
amenity=public_bookcase would be way more fitting than amenity=library
in this case.