Say a little more in the README about why this is useful

diff --git a/README.md b/README.md
index bb0ce9e644b154887f973eacf52087e9786bbe0a..fa06db824b87e7a36fac6124fffcbc0e91651a94 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,3 +1,7 @@
 # git-cache
 
 Cache git repos, much like nix's `builtins.fetchGit`
+
+When N applications that need this functionality each implement it without
+coordination, the user gets N copies of the same content, wasting disk space.
+This is an [xkcd-927](https://xkcd.com/927/) attempt to coordinate.