Unless the file itself was saved separately and linked from the email in an app-specific way you still wouldn't be able to open it directly in your spreadsheet

Unless the file itself was saved separately and linked from the email in an app-specific way you still wouldn't be able to open it directly in your spreadsheet app. That's true. You might be able to find the right mail file using text-based tools, if the mail isn't MIME encoded, but then you still don't have the file. I just found it fun to think of it as the opposite of Unix. The Nepomuk framework in KDE seems to have similar goals by the way. They kept their database separate from the filesystem, but integrated it in quite a few KDE applications. Nepomuk uses a graph database, so the schema is easily extendable. But apparently they don't even use all features of the current schema, only rating, tagging and comments appear to be consistently implemented in applications. http://userbase.kde.org/Nepomuk http://userbase.kde.org/Nepomuk