A 55% pool can coordinate their work and agree to continue to mine a block for one additional minute after a similar block was already found by a none member miner.
The pool also agree that if suc a delayed block is found they will continue to use it in the next block.
Finally the pool agree to abandon this branch if they are out computed for a second time in a row.

Let's see: it takes the pool to generate a new block at a little bit less that 20 min.
So they have a +5% chance of finding a block in the 1min.
The none members already started working on next block and in 10min they will find it,
The pool has only 9min but is bigger so there is about an equal chance for them to compute the second block first. When that happens the pool get bc of both blocks.
So income was doubled for giving up 10% of the time by adding the 1min

Question:
The motivation of a minner is to create a valid block with as much transactions as possible. Otherwise, someone else might come up with a parallele block with more transaction that will invalidate his work.
So what's keeping a miner from considering all transactions available, without regard to fee.
Or in other words, what is the mechanism by which a transaction with a higher fee will receive faster treatment?

Just a thought:

An agreed central authority (i.e. government, company) assigns the objects it governs (parcels of land, shares in a company) to owners of these objects.
The assignment is performed by sending a bitcoin to each owner and at the same time writing a document which states that the object belongs to the owner and using the same key used in the bitcoin transaction to sign the document.

Each owner can show his ownership at any time by presenting the document and proving he owns the key used as the receipient of the transaction.
This can be done by generating another transaction with the same key or by using the key to sign the document again.

Each owner can move onwership to another person by using the original transaction to transfer a bitcoin to the new owner.
In other words, the original transaction (which may cary a very small bitcoin value) is very special and should only be used to transfer ownership of the object (which maybe much more valuable than the transaction amount)

The new onwer can show his ownership by presenting the list of transactions that led to him and showing the original document and proving he has the key used as the receiver of the last transaction.

I've started developing a full bitcoin App for iPhone (or iPad or iPod Touch)
The App is made from a client that uses JSON-RPC to connect to the bitcoin server/daemon running inside the App.

In the latest release 0.0.13 I have added the option to connect to a remote bitcoin server/daemon.
So you can have your mining machine running in the cloud and connect to it while on the move.
I'm sure I have missed many things a minner needs, but there is a way in the App to enter a manual RPC command line, so I guess it can be useful for anyone.

If your interested, you are welcomed to join the team of testers at http://bit.ly/g4FNZX

If you want to develop go to: https://github.com/udibr/bitcoinApp
If you want to help go to: http://bit.ly/g4FNZX

Source at https://github.com/udibr/bitcoinApp

I've managed to run the entire bitcoind on iPhone (both sim and device) on a separate thread inside an App.
The App acts as a client and communicates using the regular RPC-JSON with the bitcoind.
The changes I had to do to bitcoin code are minimal and are described in the "Add bitcoin.org project" section of
https://github.com/udibr/bitcoinApp/blob/master/build-iOS.txt
(at some point I hope they will be merged into the master repo)

For now the only command I have implemented on the client side is "getinfo" but it should be easy to use it as a template and add all commands.

The client is implemented using Three20 package (the same SDK used by the facebook App) so it already has non-trivial features, out of the box.
For example:
* on the info page if you drag the table all the way down you can force it to refresh its content
* every bitcoind command appears as an icon on the launcher screen. It is possible to re-arrange (or delete) these icons, allowing for very nice App customization.

There are many things that needs improvement:
* the client/server response time is slow and not what you expect from an App.
* It takes a while for the daemon to start and until then if you press on the info (getinfo) button you get an error.
* If you put the App in the background the entire thing crashes...
but its a start...
once we will have something reasonable I will try to put it on the App store (not sure what Steve will have to say on this.)

Enjoy, Udi

It took me several iterations over the bitcoin.pdf to understand how it works, so I have wrote my understanding in simpler terms on https://en.bitcoin.it/wiki/Easy_Intro
You are all welcomed to improve on it or use it to explain bitcoin to others