Good post, but you have one detail wrong.
I think Open Source is not the right term here - you really meant "cross-platform". Open source means the source code is available to everybody, which would be incredibly foolish. Cross platform means that the code can be used across different platforms, and interfaces with different platforms - Openoffice, Excel, Lotus... you name it.
Heck, if you can do Spooz on Google Spreadsheets.... Spooz is going to rule the financial sector and online trading as well. But we'll see.