A client can estimate the hashing power of a miner by looking at the payouts of newly generated blocks.
He can then send his transaction like normal, but get instant replies from miners.
If a miner decides to include the transaction in his next block he will send a signed version of the transaction - signed by the private key of his payout address + attach the public key
The client can listen for these "signed by miner" transactions, verify that the public key hashes to payout address and matches the sig, then estimate the total hashing power that "promised" to include his transaction in the next(or later) block

was this already suggested?
too tired to think of security holes right now

3) Also, the scriptPubKey it's going to end up in the chain anyway. Why the moment matters so much?

If you are asking about the public key, then usually it appears in the blockchain only when it doesn't matters anymore (for one-time addresses).
So if someone can "break" the signature using only pubkey, he won't be dangerous because if pubkey is used for redeeming then that address is empty already.

the whole point of ECDSA is that you cant break it with the public key. the security issue in bip16 is that on an old client it won't even check that the key fits the sig. so there is no need to break the encryption, just get the key and script - which you can do by checking the content of the transactions that you relay or actively "sniffing" the network.

maybe i can pay African kids in btc 

something that will nag the users to update when a new version is out.
no idea how to implement
presumably put some kind of a tag in the block chain

this can also lead to different types of validation in the future:
 i.e blocks 1-100 were generated by version 0.2 - they should be validated in a certain way, blocks 100-end created by the current version, no special treatment is needed

can you make OP_CHECKHASHVERIFY to remove the last stack item?
then you can add OP_DEPTH 0 OP_EQUAL at the end of the public sig which will cause old clients to reliably fail verification unless they verify the script - i.e. support bip17.

It looks to me from reading about ECDSA that the private key can be anything - a random number
Currently a lot of users are afraid to lose access to their wallets - so they make backups etc..
I am concerned that some users will find out the private key can be anything they want and will generate\use easy to remember keys like DEADBEEF (address:1KNrMaMfiqKzRC5fzi1gqTeDC96PAqJPZy)
Whenever I need to change the password for my bank account - there is a minimal complexity required - it won't let me use a simple password.
Can something like this be implemented for the bitcoin client? some kind of a complexity check of the private key?
rejecting the key will cause a lot of trouble, but for example the client can create a new address and transfer all the funds there if a simple private key is detected, or at least warn the user that the key is bad.

I am a miner on p2pool
how does the voting process work?

Were there any special event that made BTC climb and fall so fast?

I want to run bitcoind in the background and start the gui only when needed
I have seen someone suggest to use the -server option but i didn't find any documentation on that
So, how can i make the bitcoin-qt GUI connect to a running instance of bitcoind (on windows)?

what prevents me from submitting only low difficulty blocks to a pool as proof of work, and submitting a real block, if i find it, through my solo miner to get the entire 50BTC for myself?

I am an electric engineering student and i would like to experiment with an FPGA - not specifically for mining.
what would you recommend as a cheap starter kit?
I am thinking on using it for audio/image compression/decompression and mining experiments
I am thinking specifically about fpga since so far i mostly had to deal with micro controllers and software, and now would like to experiment with hardware.
Is there a sub 100$ option?

It seems that there is going to be a significant change to bitcoin in february, so i was wondering what testing is being done.
For example in WoW and swtor - before any patch is introduced to the live servers it is applied on a few PTR/beta servers that are avaliable for everyone. This way a patch is actually tested by players on a large scale before it goes into the "real" game servers. (and there are still bugs on the live servers)
So, is there a public beta chainblock created for the purpose of testing upcoming changes?
A chainblock for people to play with "beta" bitcoins without risking anything and giving feedback to the developers on any proposed change.
A chainblock that can be safely deleted/purged without any notice.
This will also allow the developer to safely create invalid chainblocks\transactions offline to test the network's response to such an event

If I was talking about estimating the value of a USD compared to the ILS i would probably check the prices of specific items in both currencies, the government's policy on exchanging money and managing their currency, maybe have a look at the country's GDP and natural resources.
But how is it actually done?
How would you apply this to BTC?
It seems to me that currently there is almost nothing that can be purchased directly for BTC and most people exchange it for USD.
Meaning the actual use of BTC is something like: earn USD -> exchange for BTC -> send BTC to somebody else -> exchange BTC for USD -> buy products/services.
It seems that a lot of the evaluation of the value of BTC comes from speculations about the coin's future rather than its current use/value.
What are your estimations of the true value of 1BTC (i.e. its value now, without speculating about the future)?

I started mining on my GPU a few days ago and transferred 0.1BTC to MTgox to play on the market.
tried short selling , and lost about 5% since the BTC went up.
Which got me thinking. I started mining because i believe that the value of BTC will go up with time.
If i were a trader that would mean I should buy BTC for a long term profit, but since i am a miner it basically means I dont need to do a thing - i am already getting BTC, and all i need to do for a profit is not to sell them - a.k.a. do nothing. this is kinda boring...
So, If i believe the value of BTC will go up, is there any sense for a miner to trade on MTgox at all?

I am currently in a pool that doesn't mine namecoins
Is it possible to make the client mine bitcoins with the pool while simultaniously solo mining name coins (or conncting to a seperate namecoin pool)?