user105: Exactly when was the first block mined and the first bitcoins generated? How many people knew about the project at this point? Had the project been publicly announced before the first block was mined or did that happen afterwards? Is there anything special about this first block or could anyone have mined it?
I realize that there are a number of questions included here but I don't think that it makes sense to ask them separately.

user323: Exact Bitcoin timeline can be found here.
As far as I understand the first blocks were mined by Satoshi himself (probably to ensure the protocol is working correctly). The only thing special about the genesis block is that it did not link to a previous block (there was none before it), unlike all following blocks. The original block is also distributed with the Bitcoin client, so they can track any following block back to the genesis block.
Anyone can generate their own genesis block, but it will not be accepted as a part of the current block chain. Most notable non-official genesis block is the testnet genesis block. All Bitcoin-spinoff currencies also have their own genesis blocks.

user22: Bitcoin's design paper was published on cryptography@metzdowd.com on October 31, 2008, which is considered by most to be the official beginning of the project. On January 3, 2009 at 18:15:05 GMT the Genesis block was established. Six days later, Bitcoin 0.1 was released and announced on the Cryptography Mailing List.
It is hard to estimate the size of the community at any point, especially historically, but there is a decent timeline of the major events in Bitcoin history at the official wiki.

105: <p>Exactly when was the first block mined and the first bitcoins generated? How many people knew about the project at this point? Had the project been publicly announced before the first block was mined or did that happen afterwards? Is there anything special about this first block or could anyone have mined it?</p>

<p>I realize that there are a number of questions included here but I don't think that it makes sense to ask them separately.</p>
 323: <p>Exact Bitcoin timeline can be found <a href="https://en.bitcoin.it/wiki/History">here</a>.</p>

<p>As far as I understand the first blocks were mined by Satoshi himself (probably to ensure the protocol is working correctly). The only thing special about the genesis block is that it did not link to a previous block (there was none before it), unlike all following blocks. The original block is also distributed with the Bitcoin client, so they can track any following block back to the genesis block.</p>

<p>Anyone can generate their own genesis block, but it will not be accepted as a part of the current block chain. Most notable non-official genesis block is the <a href="https://en.bitcoin.it/wiki/Testnet">testnet</a> <a href="http://blockexplorer.com/testnet/b/0">genesis block</a>. All Bitcoin-spinoff currencies also have their own genesis blocks.</p>
 22: <p><a href="http://bitcoin.org/bitcoin.pdf" rel="noreferrer">Bitcoin's design paper</a> was published <a href="http://www.mail-archive.com/cryptography@metzdowd.com/msg09959.html" rel="noreferrer">on cryptography@metzdowd.com</a> on October 31, 2008, which is considered by most to be the official beginning of the project. On January 3, 2009 at 18:15:05 GMT the Genesis block was established. Six days later, Bitcoin 0.1 was released and <a href="http://www.mail-archive.com/cryptography@metzdowd.com/msg10142.html" rel="noreferrer">announced on the Cryptography Mailing List</a>.</p>

<p>It is hard to estimate the size of the community at any point, especially historically, but there is a decent timeline of the major events in Bitcoin history at the <a href="https://en.bitcoin.it/wiki/History" rel="noreferrer">official wiki</a>.</p>
