weather woeid

Hi,

I have some questions regarding weather data that can be accessed using the Yahoo weather api. I assume that when when a request is made using a woeid the closest active weather station is polled to retrieve its data. What sort of stations are are in this network? Only official National Weather Service sites?
Private personal weather stations? ( the Weather Underground makes extensive use of these ). Is there any way to find out specifically what stations are available by name and location?

Thanks,

Rudy