You can also correlate data from different sources and transform lifeless spreadsheets into interesting conclusions about the world. So you could try to find the number of Google employees over time and see if there's any correlation with Google's stock price, revenue or market share in search.
Swivel lets you use a list of existing tables or upload your own data as a CSV file (Google Spreadsheets has the option to export a sheet as a CSV file, like most spreadsheet apps).
It's important to make the distinction between correlation and causality. "A key thing to remember when working with correlations is never to assume a correlation means that a change in one variable causes a change in another. Sales of personal computers and athletic shoes have both risen strongly in the last several years and there is a high correlation between them, but you cannot assume that buying computers causes people to buy athletic shoes (or vice versa)."
