He's selling a "9G/Hash miner". What exactly does that mean?

That it "mines" 9 "G" per "Hash". That could mean just anything he wants it to mean.
And he's very happy running it.

A highly misleading listing, deliberately so IMHO, what BTC miner with 9GHash/sec would describe it thus? This is a plant.

Current bid: 3,500.32 GBP (= 50.0046 BTC) (22 Bids)

With no information, not even a picture.

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People are INSANE

You've clearly got the hang of this. My only quibble might be that your rate of increase in difficulty of 2% / day is 32% per two weeks, which may be a bit steeper than we could expect (Avalon Batch 3 are still not shipping, and BFL still at a trickle). Redoing the calc with the default 1.0306% gives diff 92M in 137 days and breakeven 44 days later (with continued diff increase).

Which explains why KNCMiner have so many keen customers. But it all turns to dust if there is any significant delay in the project (and ASICs are very prone to over-running the schedule). Remember these will be prototype devices in the first batch from the foundry, and KNCMiner  are expecting to ship these to customer. User KS pointed me at a good article http://www.edn.com/design/systems-design/4319891/The-economics-of-structured-and-standard-cell-ASIC-designs (a little dated at 2006 but still relevant). The key point being the 12-26 week delay from prototypes to full production.

Anyway this discussion is best continued on the KNCMiner threads in CUstom Hardware rather than in newbie land (hmm still only  1hr 42mins logged in, they key is to keep browsing the forums, refresh at least every 15 minutes, Mining Speculation is a good starting place https://bitcointalk.org/index.php?board=81.0 )

You would be well advised NOT to learn about PCB design ab initio using your precious Avalon chips. These are high performance devices and you need know exactly what you are doing otherwise you'll just create failure.

A couple of links to help you out (you can google for PCB stuff yourself).

Klondyke reference https://bitcointalk.org/index.php?topic=227186.0

Bitfury test boards https://bitcointalk.org/index.php?topic=228677.0

And how not to do it ... https://bitcointalk.org/index.php?topic=230525.0

KNCMiner is currently advertising the Jupiter as 350GHash/s for 6995USD https://www.kncminer.com/products/jupiter

From http://www.coinish.com/calc/ those numbers give $19 per day return at difficulty 1G, with breakeven in 400 days (for level difficulty).

So even if its covering its power costs at 4.5G difficulty, you'd better hope its delivered well before difficulty gets into the 1G range.

OK, thanks guys.

So IP logging/sniffing is the main impediment to anonymous mining. I don't think I'm quite paranoid enough to try mining though TOR, but that's useful info. Solo mining unfortunately is out of the question for all but the very largest scale miners, and I'm not quite sure how well that would work under TOR as it needs good connectivity to the major nodes (ie pools) in order to avoid orphaned blocks.

Cheers

You think? At the time of the auction the winning bidders where being called fools for paying so much (76BTC).

Use a good calculator eg http://www.coinish.com/calc/ (expert mode) for your ROI and see what you think?

PS you may like this thread by a Blade Runner https://bitcointalk.org/index.php?topic=205369.0
And this was the original auction thread at 76BTC https://bitcointalk.org/index.php?topic=178275.0
And a later one at 50BTC https://bitcointalk.org/index.php?topic=189248.0

Far too much ASIC Gold Rush Fever in the mining community right now. For a rather more critical view of KNCMiner try ...

https://bitcointalk.org/index.php?topic=228068.0 (my thread, but just crossposted from newbies, not my own views)
https://bitcointalk.org/index.php?topic=231739.0

IMHO none of the commodity kit (Avalon, BFL, KNCMiner) will be profitable for orders placed today (by the time they deliver, always late, difficulty will be so high that your ROI is never).

But if you're not concerned about profit (yes there are other reasons to mine), then OK, take a punt at it.

12 emplyoyees/directors, but only two engineers. Don't you think you're a bit top heavy? But YAY customer service!

SCAM

I invented one of these when I was eight! Drew lots of pretty diagrams, thought I was pretty clever, then forgot about it.

Then in high school physics we studied work and energy and came across the Laws Of thermodynamics (nicely described in the previous posts).

In short TANSTAAFL, a good principle to apply to everything in life (including Bitcoin).

Just thought I'd share  

Unfortunately I don't know. But I've been following the KNCMiner saga. 28nm process, claimed standard cell custom ASIC, but with no history of same, only Altera HardCopy (on same process node).

It just struck me that with Avalon, BFL, ASICMiner (I presume) all going the std cell route (with all its issues of NRE, long lead time, risk of rework), there might be an opportunity for a quick entrant into the market using FPGA to ASIC conversion (HardCopy or whatever the Xilinx equivalent is). But while much cheaper NRE than full custom, its still a significant business proposition.

Anyway, its way past my bedtime, so I'll just leave you with that thought.

No, not kiddin. Just escaped Newbie Jail myself 10 days ago. Still feel a bit sorry for the inmates.

Nothing wrong with ASICs. Other than the price. So I'm paying it forward, for a little while anyway.

ROI is important. If you're new here I guess you don't want to get burned if you take up mining.

Just do your research. That's all. Oh , this may help http://www.coinish.com/calc (expert mode).

I've been following your progress on the Open Source Fpga Miner thread, and I'm impressed (i've only got a DE0-Nano myself).

However, this is just not an economical proposition. Have you considered the Structured ASIC route? (I've been posting on the KNCMiner threads recently, if you want to take a look), I reckon this is the only short-term opportunity left to turn a profit here.

And scrypt, OK potential, but I think Jasinlee has the jump on you there http://www.litecoinfpga.com/

But best of luck. Kudos!

OK, this is pure https://en.wikipedia.org/wiki/Argument_from_authority

What amazes me is that you think you can get away with it. This isn't facebok or twitter here, you've fallen into the pit of vipers.

And BTW, talking about Argument From Authority, this post makes me a Sr Member, Woohoo, I've been here 10 days!

I asked this question earlier. You've had some time now. Do you have an answer?

Aha, my hobbyhorse!

Why do you want to buy? Magic money tree? Ain't no such thing.

Bitcoin laundering? A bit advanced for newbieland. look it up later 

So you want to know if its worth it? Look away now for the faint of heart!

Go here http://www.coinish.com/calc fill in your hash rate, purchase cost, plenty of other things to play with.

Select Expert Mode and check your "Break even considering reduction"

Still want to buy? Great, plenty of sellers on ebay or our Custom Hardware threads.

Enjoy suckers 

I'll bump you again as I'm interested in the answer too.

Re-reading your OP carefully, I think there is a little confusion about sending addresses and receiving addresses.

In the blockchain there are only transactions which move coin from one (or several) addresses to another (or several) addresses.

So transactions make the distinction between sending or receiving addresses, but the actual coin balance just exists on an address (which is what blockchain explorer shows you).

Now bitcoin_qt tries to hide all this from you by aggregating all the coin on all your addresses into your balance, and when you send some coin it just does it (by whatever heuristic was programmed in). You don't need to know the detail of the transactions, because its just easy

Now with a faucet, they need to be careful as they are sending tiny amounts (dust) so it is important to optimise the transactions, hence you see the same source address many times, unlike bitcoin_qt which sends the entire balance of a source address and splits it between the recipient and the new change address. As for why? ask Satoshi  

If you need to prove a transaction, you need to send from a specific address that you know the public signing key of. This is where I'm getting beyond my knowledge. As was said upthread, there are modified versions of bitcoin_qt that allow you to do this. And the online wallets (and probably the likes of Armoury etc) let you do it too. So let's wait for an expert again and get this resolved properly.

PS Oops, a bit stale (two posts intervening), but here goes anyway.

But this is exactly what Avalon and BFL have done. And it makes sense, from a marketing point of view. But not on the engineering side (apart from letting the experts do the custom design, which is essential). The custom ASIC business has been plagued by over-optimism from customers (ie the likes of BFL and Avalon, not end users) since the very beginning. Many tears have been shed when projects went over-time and over-budget. The current BFL fiasco was quite typical back in my time.

And it seems KNCMiner have to play exactly the same marketing game to stand any chance in this business (cannot wait the 12 months to do the job properly, hence "no prototype, no revision, bam, production". Yes it is stupid, but its the only way they can compete in the game. If they pull it off (Avalon, ASICMiner), good for them, but its risky (BFL). All these delays and the lack of communication from all of the players is to be expected (they may be in the dark themselves). This is rocketscience after all!

Since nobody is answering this, I'll bump it up for you with what I know ...

Your bitcoin_qt addresses are unique to you. There is no public pool, they are yours and yours alone. The wallet generates 100 addresses when you create it, and uses them in-order as you create transactions and sends the change back to them. Any of them can be used as receiving addresses, but only the first one is shown as your default address. If you do a lot of transactions it will create more addresses. This is IMPORTANT because if you restore an old backup of a wallet it will not have these new addresses and you will LOSE any bitcoin that was sent to them. Keep your backups up to date.

Thee addresses are good for the life of your wallet, so as long as you have it, you will receive any coin sent to them.

Perhaps a clarification. Bitcoin does not actually live in the wallets, it lives in the blockchain (on all of the bitcoin nodes on the network). Your wallet just contains the keys to access your coin (private keys, hidden by default but you can export them, keep them very safe and very secret if you do).

Doing transactions via the debug console is beyond my expertise, you'll have to wait for a real expert to come along for that info.

Sure, sure. Don't get me wrong, I dabble myself (but not going as far as full size SMT boards). It was more of a warning to other forum users who may get the idea that they can just plonk their chips down onto a DIY board and get excellent results. Not only is there the risk of burning their precious chips, but power supply is critical to getting these high performacne chips working at full speed. Take a look at BitFury's Alpha Testing thread https://bitcointalk.org/index.php?topic=228677.0 ... lots of very relevant info there.

Good luck with your efforts, at least you're having fun