Breakout boards you find on Sparkfun or Adafruit can only fit a chip. Usually these chips require decoupling capacitors, pullups resistors or the like. This board allows you to add those extra passives onto the breakout itself, making breadboard deployment a snap. Please see the sample application link for more details.
I felt inspired to make an 0603 version using solder pads that are bit bigger to facilitate hand soldering.
I think 0805 is the most popular in the wide field of surface mount hand soldering but having recently made boards with 0603 components I think it is necessary to stock a board for this smaller size as well.
I have concluded 0402 is a young/near-sighted person's game but don't let that stop you from taking that challenge!
Just posted a breakout board for SOT23-6 devices. The breakout board is SIL in design and accommodates pads to place 0805 components across any pair of terminals on the SOT23 IC. So you can pull up your signals, bypass your VCC and GND, etc all one simple board that easily plugs into your breadboard.