I've been working on a little app to monitor the twitter stream for tweets about a few coins, analyze the sentiment, and plot it on a graph over time. I've found it's best to get feedback early and often. If you have any, please let me know.

http://cryptopredicto.herokuapp.com/

There are a lot of alt coins, with new ones coming up every day.  I don't have time to track them - which ones are interesting, which ones are experiencing a surge in price, etc - so I was wondering if there are any funds out there where I can just deposit some BTC, and the fund invests in new/good alt-coins looking to generate a profit.  Does it exist?

I've been working on a book for Bitcoin beginners over the last few months, and had a lot of questions along the way. Thank you to everyone here who helped answer those questions, or took the time to review the book!

If you're interested, it's available at http://www.bitcoinbeginner.com.

If anyone here would like a free copy, pm me or email me - john@bitcoinbeginner.com

I was trying to get my head around who all the players are in the world of Bitcoin, and ended up making a network graph focused around the Bitcoin Foundation (to which most of the players are attached in one way or another).  If you're interested, here's a link:

http://blog.bitcoinbeginner.com/post/45996979908/the-bitcoin-foundation-visualized

Why not just send every transaction to every client?

Is it

- because transactions are only validated during the creation of a block?
- so that there is a way to generate new bitcoins?
- so that new clients don't have to download old transactions, just the block chain?
- something else?

It seems to me that people use Coinbase because they can buy bitcoins at 1% over Mt. Gox from their bank account. This beats (?) using Mt. Gox directly because of ease of use and no bank transfer fee. 

Now when Coinlab takes over Mt. Gox, and the fee goes down (for US folks), what's the benefit to continuing to use Coinbase?

I'm trying to wrap my mind about how transactions are secured. I've read through the wiki and I grasp how inputs/outputs work, I'm still confused about how signing does.

This is a representation of a bitcoin transaction that I've seen all over the place:



Since, I believe, most transactions are sent to a bitcoin address so the recipient's public key is not known in advance, how does the recipient claim the coins?

To use a reddit-ism, please explain it like I'm five

Hi all,
I'm trying to wrap my head around mining and I think I get it, but I have a few questions I hope someone can shine some light on.  I've read through many pages on the subject but didn't see these questions answered, or I just misunderstood what I was reading (definitely possible!).

- When a miner starts trying to hash a block of transactions, do they "choose" which transactions go in the block, or do they just throw in all transactions they've received that were not in the last block? I assume that they can, in theory, choose to ignore transactions that don't have fees, but does that really happen?

- While a miner is hashing a new block, which includes x transactions, how do they respond if a new transaction comes in? Do they include the new transactions and start hashing again, or do they ignore the new transactions?

- How does the nonce work? I'm currently under the impression that a block being hashed has x transactions which would result (always) in a given hash, so the miner changes the nonce so that they can get a new hash. Is that correct?  Could they, instead, re-order the listing of transactions in the block, and would that produce a new hash?

- How does the network resolve forks in the chain? By which I mean two miners come up with two different, valid solutions to the same block, and push their changes to the network. Some clients receive new Block A, and some get new Block B.  Those clients now start working on the NEXT block even while the new blocks are propagating, etc.  It would seem that one solution will spread out faster, but how do clients following the "bad" chain fix the error?  Do they look at a timestamp and select the earliest? Do they select the block with the most transactions? 

Thanks for any elucidation.

Hi all,
I purchased some bitcoins back in April of 2011 and didn't do anything with them until recently.  I had my wallet in my Windows 7 partition, which I don't use much anymore, but I logged in to see if I even still had my bitcoin wallet over there. Sure enough I did, and was still running an earlier version of Bitcoin-Qt.

I tried to send from that client to my new bitcoin address, but the transaction was stuck at 0/unconfirmed for over an hour. Figuring something was wrong, I upgraded to the latest Bitcoin-Qt, but everytime I tried to lauch it, it crashed.

Since I didn't want to stick around in Windows anyway, I copied my wallet.dat over to my Linux partition,grabbed the Bitcoin-qt client for Ubuntu, and overwrote the new wallet.dat with my old one.  The client seemed to recognize the old transactions fine - but my balance says 0.  The transaction I tried to send (ea0491518bb8c52f1ba514a67d5c67db0ed8ab70b78b2a19d1e1de5c9edc95c8 to address 15hVDzGnQdywsKWwmkjr2TwA83wDdYfcav) is still stuck at 0/unconfirmed.

I can't send the bitcoins again, the client says I don't have that much in my balance.

Anyway to tell the client to push the transaction to the network again?