...and why would we go around doing that when there are perfectly good solutions out there for online spreadsheets? For instance Google Docs in which I still haven't found a bug or a feature I'm missing.
Spreadsheets are necessary because people use them because they know how to use them. It is a straight forward interface that can yield good in high complexity situations.
Now most people want to use them online. And luckily there are plenty to go around.
EditGrid , Expresso , ThinkFree , Zoho and Google Docs to name a few.