What is this?

Searching the photo sharing sites, not much info on these piles and I am too lazy to register and send messages to the authors.

http://www.flickr.com/photos/tags/rockpile/?page=10

or this

http://community.webshots.com/photo/504890056/1504908900078190139CtbciO

or this

http://community.webshots.com/photo/5530953/1005532665014095406VJSFHHHGYV

or this:
http://community.webshots.com/photo/83255901/1083261881045119137wgWOSt
(This is a good one. I can tell it is out on a lava flow, perhaps in the western US? Nah, it is in Hawaii. Note these little piles are not in a line along a trail, so they are not trail cairns, in spite of the photographers comment.)

or this:
http://community.webshots.com/photo/164921327/1164945228056973798FsFuaD
(The photographer identifies this as Stow Vermont. David Lacy are you listening?)

More:
http://community.webshots.com/photo/252317580/1252324691058745256zEXMJD

Woah!
http://community.webshots.com/photo/545420172/1545437724047269387uwohRS
Says:
"Sinking Creek to Dragons Tooth AT Hike 1-14 & 1-15-06"

There is more but I stopped after page 12. Check out "Web Shots" photo sharing. That last one is a honey, isn't it?