Positive NPV vs. "The Best use of Corporate Capital"..?

Fred Wilson's recent post about Google's VC business highlights a discussion we been having in our FinMgmt course, which overlapped discussions in both ITMgmt and StratMktg. It's one thing for Venture Capital firms to take on the risk associated with start-ups, but well does that risk-management and strategic-planning work for corporations that are trying to identify positive NPV projects to create value? Should you measure activities that attempt to drive Disruptive Technologies in the same way that you measure Sustaining Technologies?

One of the comments highlights an interesting paper from Michael Porter (HBS), who is frequently referenced in our FinMgmt readings:

"A study of the diversification records of 33 large U.S. companies from 1950 to 1986 shows that diversification--whether through acquisition, joint venture, or start-up--generally has not brought the competitive advantages or profitability expected. Portfolio management, restructuring, transferring skills, and sharing activities are four concepts of corporate strategy that companies most commonly use. Portfolio management no longer works very well in the United States because of its highly developed capital market. Restructuring is merely a stopgap measure that will not build shareholder value over the long term because it usually produces an unwieldy conglomerate. Companies have the best chance of being successful at diversification if they capitalize on the existing relationships between business units by having them transfer skills and share activities."