Don Park thinks that a competitor smart enough to leverage the open source community should be able to run circles around Documentum. But things aren't quite what they seem. If you take a look at Documentum's Financials, you'll see a bit over half of their operating cost goes to sales and marketing. And that sales and marketing costs are 2–3× R&D costs.

If we assume that Documentum Sales and Marketing is competent, then an open source alternative probably can't afford to compete with them. Of course, open source could go after a different market segment and grow to compete with Documentum a few years from now.