- 22 – Laszlo Hanyecz, a GPU miner, makes the first documented purchase of a good in exchange for bitcoins; two pizzas for 10,000 BTC.
- 07 – Bitcoin v0.3 is released.
- 11 – News of the latest release propagates to Slashdot, causing a large influx of bitcoin users.
- 12 – Bitcoin value begins rising rapidly, going from $0.008 to $0.08 over the next five days.
- 17 – Mt. Gox is established.
- 18 – ArtForz becomes one of the earliest GPU miners.
- 15 – 184 billion bitcoins are created artificially in block 74638. 53 blocks into a chain fork, the updated chain overtakes the erroneous one and the fraudulent bitcoins cease to exist.
- 14 – Block 79764 is the first to be solved with split allocation of the block reward.
- 18 – Jeff Garzik pays puddinpop 10,000 BTC (~$625) to make their Windows-based CUDA client open source.
- 29 – kermit discovers a glitch that prevents transactions referencing small outputs from being confirmed.
- 01 – The first public OpenCL miner is released.
- 07 – The exchange rate begins rising again, from $0.06.
- 16 – The earliest documented escrowed transaction occurs between nanotube and Diablo-D3, with Theymos as the escrow.
- 28 – The earliest documented short sale occurs between nanotube and kiba.
- 06 – The market capitalization reaches $1,000,000 as the exchange rate passes $0.50.
- 07 – ribuck sends 0.42 BTC to doublec in the first mobile-to-mobile transaction.
- 09 – Difficulty surpasses 10,000.
- 09 – The earliest documented sale of a call option contract occurs between nanotube and sgornick.
- 13 – Satoshi Nakamoto logs out of BitcoinTalk for the last time.
- 15 – The Bitcoin Wiki is reestablished by Mark Karpelès using MediaWiki.
- 16 – The earliest documented pool-mined block is solved by Bitcoin Pooled Mining, aka Slush's Pool.