I don't understand your comment. It's not far fetched to have millions of rows to handle. I myself have about 12 million rows (notes mainly), although I don't load everything at the same time, so maybe you're referring to that aspect?

It's pushing the boundaries of a spreadsheet's practical usability to be honest. I would not use it for more than a few hundred at most. In fact I just checked my largest sheet is 292 rows. Anything larger goes in anything else! Usually I use SQLite for local storage data like that now.

A funny problem I had a few years back was a company with users keeping 200 meg+ Excels sheet on their desktops. It took them forever to log off every day because the profile was copied back to the server.

How to you get immediate feedback while doing edits/calculations and also collaborate after you stash your data in anything else?

Oh yes, I’m one of those users (and who are “those”? Lizard people?). At least once a week I need to operate datasets that have hundreds of thousands of rows, and while accessing them is not a problem, batch computations can be tricky.