Comment by pianoben

This change makes me SO HAPPY:

    The math/rand package now automatically seeds the global random number 
    generator (used by top-level functions like Float64 and Int) with a random 
    value, and the top-level Seed function has been deprecated. Programs that 
    need a reproducible sequence of random numbers should prefer to allocate 
    their own random source, using rand.New(rand.NewSource(seed)).

We've had some truly nasty bugs from people who weren't familiar with the prior behavior of having a default seed of zero for the global random-number generator. This is going to save many people so much heartache.