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I don't typically use spreadsheets, but from time to time I receive one from someone and am reminded how handy they can be. Basically, with just one click, spreadsheets can sort alphabetically or numerically; change values and recalculate financial projections; import data from other sources on the Internet; or develop and crunch scientific data.

I am by no means a "power user," but if you're willing to learn, spreadsheets can be a valuable tool.

Microsoft's Excel is probably most popular spreadsheet software around, and some estimates - based on the ubiquity of Microsoft Office - put the number of users at close to 20 million. The majority of these users work on Windows-based computers, but Office runs on Macintosh computers, too, and the files are easily transferred between platforms.

The old-but-still-in-use Mac-based office suite Appleworks includes a spreadsheet program, as does Apple's new office suite, iWork with its Numbers software. Also, OpenOffice includes Calc, a spreadsheet, with a lot of support from the open-source community.

But before electronic calculators and computers, producing a spreadsheet was a big deal because they were tabulated manually, with pencil and paper, and later with mechanical adding machines.

Can you imagine calculating the rows and columns of spreadsheet by hand? Working up a spreadsheet in the old days was no simple decision. The office had to ask if it was worth the time it would take: What will a calculated spreadsheet tell us? Do we really need the figures? At the time, those weren't casual questions.

The first computerized spreadsheet came in 1979 and it also was one of the first applications written specifically for the emerging PC industry. The new computers of the time were great toys, but a PC needed to be useful beyond playing games for the business world.

As the story goes, according to Wikipedia, Dan Bricklin was in a college class watching a professor laboriously recalculate a financial model on the blackboard. He realized there was a better way using the new Apple II computer; all those calculations could be done on the fly, he thought, automating the once time-intensive task. So was born Visicalc - the first computer spreadsheet. (You can learn all you want to know at the Visicalc Web site,


Many people consider Visicalc to be the first "killer app," an application that changes the direction of either the computer industry or the business the program targets. A "killer app" provides a single reason for a person or a business to buy a computer, and with about 20 million users, the modern version of Visicalc - Excel - seems to have done just that.

Today, some say spreadsheets often have replaced more by-the-seat-of-the-pants decisions. Spreadsheets are so easy to use that calculating a business's potential for growth and developing sales projections, it is argued, are based solely on numbers rather than past experience, intuition or other factors. For example, it's easy to calculate projections for a lemonade stand after a sunny day of sales, but when you order a case of frozen juice without taking into account the weather forecast or the location, it doesn't do you much good.

Spreadsheets aren't used solely for calculating financial data - they can be used something like databases, too. One click on a column sorts that column. Spreadsheets aren't as efficient as databases for work that is search-intensive, but they can be convenient for a few pages of data that need to be sorted.

Three points to be aware of with spreadsheet documents:

n The default file extension for spreadsheets is .xls (you'll also come across different extensions for .xls templates). Microsoft's Office 2007 introduced new internal file formats based on some open-source concepts, but all versions are backward compatible. Appleworks will import older Excel .xls files, while iWork's Numbers will import all Excel spreadsheets, including the newer formats. Calc can import older Excel files and export in an Excel format that can be converted to the newer format.

n Excel and other .xls files are vulnerable to viruses because they allow macros to run. A macro is a small program that automates work done in a spreadsheet, such as formatting for mailing labels and deleting empty columns, and because macros are programs they also can be viruses. Usually, viruses only affect programs, but macro viruses infect the documents themselves and can thus be transferred across platforms, between Windows computers and Macs. Most anti-virus programs will detect macro viruses, and Excel will allow you to turn off macros so viruses can't run if they are present.

n And, as with any file, be careful where those Excel files are located on a business network so they aren't accessible to the outside world. A popular hacking trick is to Google for file types, and you'd be surprised how much personal and financial data a search can turn up on the Web in erroneously accessible spreadsheet files. In a few minutes' search I found business financial reports and obviously private mailing lists.

Follow-up: For more information on file extensions, check the File Extension Source at, which lists almost 25,000 and offers toolbar buttons to quickly search a database for unknown extensions.

Mark Ratledge is an information technology consultant in Missoula. Contact him through his Web site and blog at

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