Editor: ROI distribution
The ROI distribution among deployed projects is clearly not normal, but closer to power law. The median ROI is in 125-150% range.
Also, we note that over 1/3 of those who deployed the project do not know the approximate ROI.
For data mining to be seen as a useful business tool, ROI should be measure, so I want to encourage all data miners whose work was deployed, to find out their ROI, at least approximately.