As we all know, open source matters:
In a couple of days, it’s Document Freedom Day. Open document formats are about having documents available freely for everyone. It serves the cause of interoperability and does not force anyone to use a specific program or operating systems.
Example: There are a few really cool text processing tools like Abiword or OpenOffice.org (cool PDF-export function in OO.org by the way) and they both support the Open Document Format (ODF). They can also edit the Microsoft Office Formats. They cost you not a thing and you’re sure that everything is displayed in a proper way on the other side.