Turing completeness of Bitcoin Script

For me, scripts are one of the most interesting features of Bitcoin. They provide possibilities which have no equivalent in classical currencies. However, the wiki states

It is purposefully not Turing-complete, with no loops.

  1. What’s the rationale behind this decision?
  2. Are there any proposals for useful contracts which would only be possible in a Turing complete script implementation?
  3. Are there any alternative crypto currencies with Turing complete scripts? If so, how do they solve the problems from 1?

Is there an opensource crypto-currency exchanges engine?

I’m looking for an opensource crypto-currency exchange engine.

My preference would be for something easy to use like joomla or drupal. My exchange setup needs support for alt-coins and bitcoin.

I have discovered intersango myself. However, sql file is corrupted, there is no creation of tables and import does not work. Plus it is bitcoin exchange only (and I need alt-coin support). Site of this exchange with “invites only”, registration is closed.

Is there something super-simple that I can use to get started?

Who created the Bitcoin blockchain?

Satoshi Nakamoto wrote the theory about Bitcoin in his paper, but did he (or they) also launch the Bitcoin blockchain?

Like: Peter Higgs founded the Higgs particle in theory, but he didn’t find the actual particle…

What is the strategy behind a sell wall?

I understand the idea behind ‘bid walls’, but on Kraken, prices are being kept low through the use of ‘sell walls’. The volume on this exchange is too low to have a chance of getting through these walls, even when prices on other exchanges are skyrocketing. Every so often, when the price falls a bit, up comes a new ‘buy wall’ keeping it there. The price on Kraken falls when other markets fall, but gets stopped at the wall on the way back up. I am curious to know what the strategy behind this tactic could be.

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Added 21 Nov for elucidation

On this small volume exchange, a 30 BTC ask equals 10% of the 24hr. volume. It is the equivalent of a 4500 BTC ask on Bitstamp. It alters the way bidders approach the market. When you see such a wall sitting just above the current price, you can be sure the price will not be rising beyond it for at least the next few hours.

I watched this person re-position this block four times over the course of the day. Each time, lowering it to sit just above the current bid price. It was altering the dynamics of this small volume exchange.

I am not asking for you to read anyone’s mind. I was baffled by this behavior. I had not seen this strategy before. I thought that there must be some method to this madness, but I could not see what I might be. I thought that somewhere in the collective experiences of Stack Exchange there might be someone who was familiar with this strategy and might be able to provide some insight, not necessarily on this person’s behavior, but on the theory behind the strategy being employed. Assuming, of course, that there is one.