It appears that the gap between buy/sell orders is too small for day trading. Therefor, I presume most trading is done by investors buying from miners.
These are probably sold by folks with large caches of bitcoin. Once the large caches are sold down to what the early adopters are comfortable with holding, then the supply of bitcoins for speculators will decrease. Hopefully by that time there will be some useful smartphone clients that restores the confidence in bitcoin growth. As the supply decreases, then the demand should increase. With each new technology announcement, bitcoin prices should then see steady growth. I expect this to happen in about 5-6 months at the latest. I'm guessing that early adopters will collectively hang on to no more than the first million or so bitcoins because they want to see the technology thrive. I am presuming a few things, but that is what speculating is about.
5Mbtc/30kbtc per day being traded averaged out over the last month is how I arrive at 5-6 months.