I wrote earlier about
how you will pay for Bitcoin network access in the future. In short there are lots of reasons why people will want to run full nodes, from simple payments like amincd mentioned, to stuff like datamining and advertising. Giving out a free service in exchange for data to feed into search engines and/or sell to companies and governments is very profitable, and running a node that, say, people's Android wallets connect to lets you link transactions with actual identities. For instance you could sell the data to governments trying to track down tax evaders by analyzing transactions on the blockchain.
I think that only a few major players would survive even if there were profit. Because, the data can only be sold once. Once someone know that this account is associated with one person they would not have to buy that information again. They can just grab the transaction from blockchain.info or by running a full node themselves.
And more importantly, would you really trust a bunch full node owners that would sell your data in a heartbeat?
Wouldn't the system be more secure, if a bunch of people who know nothing about programming run full nodes? For that to happen, you need to give people incentive to do so.
I don't think full nodes will need fees until the blockchain is 10-20GB, at that point the average person would stop running full nodes.
The average person is already not running a full node because of e-wallets and electrum.
I operate several well connected full nodes. I see no need for a change of the block fee but I would like to see additional filtering. This is necessary to prevent the miners (or better the pools) from getting to much power and doing things that are not in the interest of other users. A current examples are pools that take the block fee but do not include additional TX into their blocks.
Thank you for running the full nodes.
If the systems pay people for running full nodes, we can destroy the miners monopoly on the supply of bitcoins. This improve circulation of bitcoins, which in turn reduces scarcity that is the main reason for today's poverty.
A question:
If all the top miners collaborate to hoard the bitcoins they mine, where would the bitcoins come from for everybody else?
How would people with no bitcoins obtain a bitcoin? Without subjecting themselves to the control of whoever has a bitcoin.