если есть возможность,почему бы и не помочь немного?

Заняться бизнесом.

бывало,но редко

Самое прекрасное время в моей жизни.

Nope. If the private key is lost, the coins are absolutely gone and no one can be forced to spend his/her bitcoins.

Okay. Bitcoins are stored in the blockchain. Every client on the bitcoin network has a copy of this blockchain. The only way to access these bitcoins is with the private key to which they've been assigned. These private keys are what's been stored in your wallet. This means that only you can access your bitcoins, provided only you can access your wallet. This is why having a wallet on a thumb drive is more secure, as it means only you can access your bitcoins. Compare that to using MyBitcoin. As they're the ones with the wallet now, they could ostensibly take everything you have (to which you've allowed them access).

Pass it the account's label.

I would recommend using #bitcoin-otc, but there's not really any correct place. Anywhere you can find someone willing to purchase your item with bitcoins is good. You're right that this board isn't really the right place, but you can try the Marketplace board or one of its children. Things are bought and sold there quite frequently.

There really aren't bitcoin laws. You can buy/sell anything using bitcoins, we can't stop you (your government is another matter). That's part of the beauty.

For a block to be accepted as valid, its hash must be of a lower value than the current target. As a result, the lower the target's value, the harder it is to produce a valid block, as there's no way to know what will lower the value of the hash of a block without generating a hash. Essentially, you're attempting to brute force a low enough hash. Every 2016 blocks, the client looks at the rate at which blocks are being generated and adjusts the target accordingly such that it should take about 10 minutes for the network to generate 1 block. This ensures that even if someone did pull together an amazing amount of hardware, they couldn't generate an obscene amount of coins, keeping it from the rest of us (not for long, anyway). There's no central authority on difficulty, each client generates it individually. As each client has an identical block chain, however, each client comes up with the same target.

It's certainly possible. As far as probability, I'm not so sure. It seems to me that there will always be at least a few people trying to make a few BTC with their old computers, not really caring whether or not it's profitable.

$15.60

Wait, are they all backups of the same wallet? If they all contain the same keys, then there's no reason to keep any but the latest, as it should contain all of your bitcoins. If they're separate wallets, i see no reason to have more than one if you're just going to keep them all in the same zip folder.

Yep. If you want, you can find the exact numbers for calculating the probabilities on the wiki.

If all you need is a CPU miner for linux, i recommend jgarzik's miner. http://forum.bitcoin.org/?topic=1925.0

Looks really cool. Can't wait to see the finished product.

The page will report an error until the transaction is encoded into a block.

It's located at /home/<user>/.bitcoin/wallet.dat

I thought it seemed like a really cool idea. It piqued my curiosity.

I'd be happy to sell an invite. PM your email (or post, whatever) and send 0.1 BTC to the address in my signature.