And the truth shall set you free.  Transaction fees.  Thanks for the responses.

It seems the steady-state operation of the network is more dependent on fees than I originally realized.  But that makes perfect sense.  It also makes sense why the block reward is initially high.  Bootstrapping.  

Oh, hai there!

I'm about to buy some of your physical coins as Christmas presents.

I understand that the cost of adding transactions is negligible.  Still, is there any enforcement mechanism?  Can I receive a handful of transactions and then just get to work on solving the block?

I seem to remember something in the protocol specs about checking the timestamp of the latest transaction in a solved block or something like that.  But it wasn't clear, and I can't remember where I saw it now.

Anyway, it's not hugely important, but it has been bugging me.

Fellow n00bs,

Does anyone know what incentive or protocol rule compels miners to add new transactions to a block they are working on?  It seems like adding new transactions is a waste of processing power.  Why not just receive a few transactions and then get to work?

At least someone in here knows how to spell meagre correctly.  Cheers!

I have been trolling hard for a not insubstantial period of time only to find out that I am doomed for the present time to post only to this forum, this thread of which, at least, seems very narcissistic.