Recently as I think about this project the background processing part of my brain turns up some words which should help located it in a google search, and after a bit of seraching I found the article. So I'm posting it here so I can find it again.
Here are a couple of good quotes as to the mistakes made:
Uncontrolled feature creep. Kapor originally conceives of Chandler as a complement to Microsoft Outlook targeted at "'information-intensive' individual users and small companies." But everyone on the Chandler team has a different vision of what that means, and in the absence of pressure to ship, Chandler becomes the union of everyone's ideas. Instead of borrowing from successful similar products like Outlook/Exchange, the Chandler team is determined to invent something entirely new from first principles. They want to support user plug-ins and scripting, built-in encryption, storage of messages in multiple folders and infinitely customizable user views. As the project goes on, the simple replacement for Outlook/Exchange grows more and more complicated.
No decision is ever final. Time and again, the Chandler team hashes out compromises on complex issues, only to hit reset when someone new joins the project with new ideas or when it turns out that someone wasn't really satisfied with the compromise. They revisit their choice of database layer, whether to use Mozilla's UI primitives or wxWidgets, and the whole design of their user interface. Eventually, the peer-to-peer architecture is abandoned in favor of a client-server architecture. Three years into the project, the team is still debating whether to turn Chandler into a web-based application like Google Docs & Spreadsheets.