Open source software is at the opposite end of the spectrum. The source code is included with the compiled version and modification or customization is actually encouraged. The software developers who support the open source concept believe that by allowing anyone who's interested to modify the source code, the application will be more useful and error-free over the long term.Open source is a great way to save money instead of buying Microsofts expensive $300-$1000 Microsoft Office. It also is easy to function and operate. It is also very compatible and can save as many other formats.