Depressing. This is like that movie with Robin Williams "The Final Cut". http://www.imdb.com/title/tt0364343/ A total privacy nightmare. Your government is gonna love it though.
Yeah, this is a really cool idea, but only if you have full control of your data. Ironic that they should mention "full control" as an argument in favor of storing the data on someone else's server.
You're only a subpoena away from having every intimate detail of your life revealed to the authorities, unless you manage to turn the camera off whenever something potentially suspicious happens (this is also called circumstantial evidence).
There's no way to have full control. You might get to have full control over photos your Memoto snapped, but I sure as hell can think of no way to get full control over photos of you snapped by someone else's Memoto.