I spent today researching various information sources, and found OANDA's analytical tools very interesting. OANDA reports an aggregate of their clients' orders and positions for free, which is useful if you're trying to measure retail sentiment. They also provide the weekly Commitment of Traders (COT) for free, although it doesn't include commercial positions.
Anyway, I was looking at their order book and confirmed the theory that stops accumulate around big round numbers.
The above snapshot is interesting, since it indicates that retail traders seem to be more bearish than bullish on the USDJPY, considering there are more sell orders on the upside than there are buy orders on the downside.
Contrast with the CoT report on the JPY, which indicate that the large money is bearish on the JPY (and thus bullish on the USDJPY).
It seems contradictory, but we have to bear in mind that retail money is generally referred to as "dumb money", and the smarter bet would be to go with the large money (aka the "smart money").
I'm also beginning to appreciate why it may be more sensible to concentrate on a handful of currencies if you're going to delve into fundamental and sentiment analysis. There's alot of information to absorb.