That is one challenge when working with a pseudonymous digital currency -- even simple metrics like "total [real] spending volume" are very difficult to report on accurately.
Some of that was funds from addresses with large amounts of funds. Sending 0.01 btc from a bitcoin address that has 10,000 BTC on it may make it look like that was 10K of funds moved, not 0.01 BTC of funds that moved.
Additionally, with the bitcoin client released with encrypted, those volume metrics could have been transfers to accommodate having an encrypted wallet.
If there was a jump in the adoption rate of Bitcoin, with it being used in a significantly greater manner then the number of transactions would have jumped as well: - http://blockchain.info/charts/n-transactions