- 
          Default constructors don't allocate memory which improves performance and
          usually implies a no-throw guarantee (if predicate's or allocator's default
          constructor doesn't throw).
        
 
- 
          Small string optimization for 
basic_string,
          with an internal buffer of 11/23 bytes (32/64 bit systems) without
          increasing the usual sizeof
          of the string (3 words).
         
- 
          
[multi]set/map
          containers are size optimized embedding the color bit of the red-black
          tree nodes in the parent pointer.
         
- 
          
[multi]set/map
          containers use no recursive functions so stack problems are avoided.