Paul Saffo at the Institute for the Future has pointed out that in a two-year period, less happens than we would have thought, and in a ten-year period, more happens than we could have ever imagined.This is so absolutely true, and likely the one of the most difficult challenges to being a venture investor. Timing is everything, not only from an sales & product adoption perspective but also from a ROI angle. A 3x return in one year is a homerun, whereas a 3x return in eight years is less appealing. Predicting when to invest money in a given growth stage business and knowing when to jump on board just before the point of maximum increasing sales/adoption growth, to maximize returns, is an art mastered by only a few.
Pip Coburn posted (some months ago) an excellent discussion piece on timing expectations held by technology investors. He's synthesized an always-enlightening subject on technology adoption patterns, and it's effect on establishing realistic expectations for the future.