The markets that do the sort of high volume, low margin trades that would be affected by an FTT are the foreign exchange (FX), futures, options and stock markets (with special reference to high frequency trading of the often demonised computer algorithmtype).
It then used this knowledge to create a predictive algorithm that guesses what you're likely to type next, suggesting three options above the keyboard as you go.
At the University of Sydney, in Australia, Steve Manos used an evolutionary algorithm to come up with novel patterns in a type of optical fibre that has air holes shot through its length.