It's nutritious as a pot-herb, but also valuable (historically) as a fiber plant, and as a plant with story-meaning, too.
Nettles are interesting and widespread. They're native to a good chunk of the world (http://en.wikipedia.org/wiki/Urtica_dioica) in North America and Europe, but they're certainly prolific in other places, too (in overgrazed areas around Masai dwellings in Tanzania, for example).
I saw a patch recently in a pasture (at Biltmore Estate). It was prolific and spreading. It echoed an overgrazed spot, I'm thinking.
|fall view at Biltmore|