The emphasis on supporting small casual transactions seems to have created a number of problems for the bitcoin infrastructure. Mt. Gox charges a small % for transactions (rather than a flat fee), a by product of this is it allows people to flood the exchange with a ton of micro transactions without any additional penalty for the volume of orders. Seems like this could be part of the reason they have been having issues.

Doesn't this also impact the block chain in some way? A ton of small transactions can flood the chain, requiring more computational energy to be spent than the transactions are actually even worth.