Thank you for the great feedback on Project Sage.  After thinking about your comments, I have iterated a bit (in my head) and wanted to share my latest thinking with you.

The key objective of Project Sage is to capture collective wisdom on key assumptions made in spreadsheets — turning an individual spreadsheet into a wiki-spreadsheet, if you will.  

So, here are some updated thoughts on Project Sage:

1.  Allow users to upload any existing spreadsheet (Excel, Numbers, 1-2-3, Google Docs by URL).  Like Slideshare, but for spreadsheets (Google and Zoho allow you to upload and share a spreadsheet today, but the use patterns we are focused on here are closer to the way Slideshare is being used).  

2.  Present a web preview of the spreadsheet to the creator.  In creator view, show the data values in one color (blue) and formulas in another color (black).  Allow the creator to turn any data value into a user-editable field.  For example, a creator could upload income statement projections for the Fortune 500 into Sage.  He could then make forward revenue and expense growth values / growth rates editable [by any registered user] fields.

3.  Provide some basic visual editing tools, similar to those available at the major blogging providers.  Provide templates, color and font selection, and allow the creator to edit his URL — use sage.com/date/name_of_spreadsheet as the default.  Encourage the user to enter tags and related URLs for SEO.  And provide basic analytics to the creator.

4.  In advanced settings allow the creator to change the statistical function applied to the data munging process — arithmetic mean, geometric mean, exponential functions, Bayesian probability.  Also allow third party developers to insert their own treatment with a snippet of Python or some other scripting language.

5.  Insert a comments pane below each spreadsheet and give the creator comment editing and anti-SPAM tools — again, very much like what you would find on a blog.

That’s it.  Now anyone with a spreadsheet can tap The Wisdom of Crowds.