I don't use TOR but I do use a VPN. However that is mostly because it gets me around some draconian download caps (at the cost of putting me last in line for getting any bandwidth).

It should not be a problem

The bitcoin protocol is designed so it is almost always more profitable to follow the rules than to break them. Its not hard to trust that people will want to make money.

The author of that article does not suggest that the core bitcoin devs should work on these issues directly but should rather focus on making it easier for others to add these things on top of the bitcoin protocol.

ah ha I think I know what the problem is. Some how you associated .dat files with bitcoin.exe so that when you double click one windows lauches bitcoin and sends it a command to open the file. Bitcoin sees a incoming command from outside the program and checks to see if there is a password so it can know if it should follow the command. Since there is no password in the .conf file it gives you an error.

You should never have to tell bitcoin to open the wallet.dat file it will automatically find the one in the correct location. To restore a backup you just need to copy the backup to the right location while bitcoin is shut down then reopen bitcoin.

You should never need to open the wallet.dat file and if you do open it you won't use bitcoin.exe to do it, you will use a wallet editing tool.

How are you running bitcoin normal? A shortcut? A .bat file? If either of those try double clicking directly on bitcoin.exe. If you still get the error look in the same folder where your wallet.dat file is for a file called bitcoin.conf and if it is there open it in notepad and look for a setting there.

If you don't get the error when clicking directly on bitcoin.exe check the properties of your shortcut or the contents of the .bat file. If you see some thing like C:\...\bitcoin -server remove the -server.

If you try all that and still get the error then I am out of ideas.

Edit: The reason you may of ended up with server mode on is that it is necessary in order to do solo mining with a separate mining program.

That error is not from interacting with the wallet.dat file it comes from trying to run bitcoin with the -server option enabled without having a password set. Running with the server option on and no password would mean anyone who could get past your firewall and router could spend your bitcoins. So the software does not let you do that.

Once you receive some bitcoins you should make sure you have your wallet.dat file backed up, preferably encrypted.

It can be found

C:\Documents and Settings\YourUserName\Application data\BitCoin (XP)

C:\Users\YourUserName\Appdata\Roaming\BitCoin (Vista and 7)

The wallet.dat file contains the information necessary to spend your bitcoins.

Every time a new block is found or a transaction is added to the block you are working on you end up working on a different problem. Also there is no guarantee that the problem you working on at any given time even has a valid solution so there is no incentive to avoid adding transactions or ignoring a new block that shows up.

Edit: to get more specific about the problem being worked on, it is a guess and check sort of problem with you computer making millions of guesses per second each of which has an equal chance to find a acceptable solution (a cryptographic hash that is lower than a certain value).

I would say it comes down to: who do you trust more the internet cafe or mt.gox/mybitcoin. To me it seems trusting mt.gox is safer than trusting a internet cafe computer to be free of virues.

If you are running an older version of the software you may need to run bitcoin.exe with the -rescan option after putting your wallet.dat file back for the balance to show up properly.

If your not familiar with the command line the easiest way to do that is to create a .txt file in the same folder as bitcoin.exe, type "bitcoin.exe -rescan" into the file then rename it something.bat and double click it.

GUIMiner is for mining only you need a separate program for sending and receiving bitcoins. You can find the standard client at bitcoin.org

Once you install the client it will take a while to download the block chain (transaction history) from other users once that is done you can start sending bitcoins. You will be able to receive bitcoins as soon as you have an address but you won't be able to see them in the software till you finish downloading the block chain. ATM the block chain is 128592 blocks long. This is displayed in the bottom right of the software.

The estimate being wrong would not be a big problem if there were a way to resend an existing transaction with a fee (or a bigger fee) attached. For the gui I would think the right place for such a command would either be right clicking the 0 confirmation transaction or in the window brought up by double clicking the transaction.

Having more money does you no good if you never spend it. People will spend rather than save for the same reasons people take out loans to buy things despite it being cheaper to wait and save up ahead of time.

They may spend less and more carefully but that is not necessarily a bad thing.

One solution would be to create a second encrypted copy of your wallet with a different password from your day to day use one and give out that password to trusted relatives. You then keep that second copy in a safe in your home so you can update the files as necessary.

If your safe is broken into and your bitcoins are stolen you can be fairly certain that it was one of the people you gave the password to and not a virus or key logger that got you.

If you want to be able to know exactly who stole them you could even create a separate encrypted copy with different passwords for each person with each one missing one private key with a very small amount of bitcoins available to it. If you find your self missing all your bitcoins except one of those addresses you would know who to go talk to.

As for stealing fund between your death and inheritance being given out and transactions between your death and the distribution of inheritance should be fairly easy to spot unless they are careful about pruning keys from the wallet.dat file.

There have been big drops in the past and regular dips over weekends when money stops flowing into peoples trading accounts.

The first link on that page goes to the address the funds came from. The reason for that pattern is when you spend bitcoins you send an entire group of coins you received in the past split between the person you sent them to and a new address belonging to you.

Specifically what you are seeing is probably some one sending out small portions of a large group of coins. The reason the balance goes up after each link is because you are going back in time.

I would guess the source of the transactions is a mining pool operator making payments to pool users.

Two ways for it to happen you can spend them and pay the fee, they will arrive as a single unit. Alternately you can send small batches to another address you control (say at mybitcoin, mtgox or bitcoin running on another computer you own) and then send in larger chunks from there till you can send them all at once with no fee. You have to wait some time between stages of this process for the transactions to mature to the point where they won't need a fee just because of age.

First bitcoin is global and it is always night somewhere. Secondly most places power is cheaper at night and cooling is easier.

Fees for a transaction need to be based on the load the put on the network by that transaction since those fees help support the network.

Coins split into very small amounts can regain their full purchasing power if you use small free transactions to combine them into larger chunks. This would take some time though as if you tried to do it quickly the short time between spends would prompt a need for a fee as well.