I'm in favor of annoucing it on the talk list, and go to vote, what do you think ? Sletuffe 18:30, 25 March 2009 (UTC)
Yes, let's get this moving. Badly needed feature Jamesks 18:34, 30 March 2009
- I would not personally use this for areas but would certainly use it or place=valley as a node for capturing names for search purposes. In Yorkshire, UK, for example, there is a great sense of community around the valley you come from. Some of which are not connected to the river, for example Wensleydale and the River Nidd. For each populated place, I (already) add a tag is_in:valley=Wensleydale MikeCollinson 10:23, 15 July 2009 (UTC)
Very often, valleys are part of other bigger valleys so we have to think about a good relation criteria: my considerations are similar to those I took on Massif discussion .
We really need this tag. There are a lot of important/touristic valleys almost world-wide know but not present in OSM. The solution of MikeCollinson of using only a node is usable, but for bigger valleys I think it's better to delimit it with an area.
About the fuzzyness: the water basin usually is enough to delimit the valley at the right and at the left of the main river. Sometimes the same water basin of the main river, can be cutted longitudinally to delimit different names (valleys).
For example: the water basin of Avisio stream in the higher part is called "Val di Fassa", in the middle "Val di Fiemme" and in the lower part "Val di Cembra". In this case even if the water_basin is the same we should use three continguous different elements natural=valley.
--Alessioz 15:55, 5 September 2009 (UTC)
I just found this relation that in my opinion is perfect for natural=valley as well as for natural=massif/mountain_range 
--Alessioz 12:57, 6 September 2009 (UTC)
I think it should be also possible to tag valleys as ways going through the middle of the valley - like streams use to. This way no fuzziness is necessary.
--*Martin* 9:27, 22 October 2010 (UTC)
I have just added category_type=valley to Relations/Proposed/Region, which nicely covers Valleys with possibility of nesting. If you have any ideas please come to Talk:Relations/Proposed/Region#Valley --Jakubt 21:24, 14 October 2009 (UTC)