1) Real time list of blocks, including orphaned ones
I think, this could be also useful also estimating - how blocks to wait for considering transaction fixed in block chain.
Ex. if statistics shows, that one block is orphaned with 1% probability, 2 blocks with 0.01%, 3 blocks with 0.0001%, so it does not require to wait 4th block if you are not afraid of <0.0001% probability.