Reviews and Ratings
Each day I travel to and from my workplace on a bus for some 35 minutes: thanks to monotone and its distributed nature I can not only hack at code on my laptop in that time, but also commit changes, diff and annotate and do everything with any past revision of the software I'm hacking at.
Everyone can work in a completely local way, needing only to sync to each other; there is not even need for a "central" server, only one (or more) places where people agree to exchange data, but if that goes offline, every single use has got it all, and can create a working mirror with the use of a single command.
The authors have always chosen the safest approach to data, every single commit is digitally signed, everything is mirrored on every node, everything is secure to the point that even in the first months of development many data-content problems turned out to be actual HDD failures and not problems in monotone.
I love this software.