Daily transaction volume is up a solid 20% over where it was at the beginning of the year.
- http://blockchain.info/charts/n-transactions
That can be manipulated easily but the trend is probably fairly accurate. That chart tells more about how actively Bitcoin is being used than the trend of the number of users running as nodes tells. The dropoff in nodes might have been exacerbated from those who were mining solely for the "free money" and now that a good chunk of lower-end hardware isn't productive enough it makes sense that their nodes have since dropped off the network as they've quit mining.
Though Bitcoin isn't gaining huge traction as an ecommerce payment method yet and retail / point-of-sale is virtually nonexistant for now, Bitcoin does seem to be used for international payments and remittances, for speculation and for other uses that let Bitcoin just keep on keeping on.