After submitting a correction for Apple Maps when they got the name of the Gulf of Mexico wrong, I wrote a letter to Investor Relations: http://a.9srv.net/b/investor_relations

One of the things I love about Plan 9 is how the interfaces make this possible: add snapshots to any block storage, at the kernel level, in less than 700 lines of code. http://9p.io/sources/contrib/blstuart/snap/devsnap.c