An indicator that multiply the closing price with the current volume. (close X volume)
This will show the relative interest in the underlying asset regardless of the price change over time. For the case of FXCM, when the price fell from $16 to $1, its volume spiked 16x at the same time given the fact that 16x more shares can now be purchased with the same...
Combined the RSI inverse of gold to USD with the Dollar index (or whatever stock symbol that may be inverted/complementary) with another asset/currency, like bitcoin, you can basically be well informed when a potential move is on the horizon. Settings allow for inverse settings and de-combining the two pairs as well as a nice cloud look if all the lines get annoying.