A frequently overlooked point of lock-in with Microsoft Office is its default use of proprietary fonts. Contrary to the popular view, fonts are often not freely distributable, and may in fact be covered by restrictive license terms similar to proprietary software. Microsoft Office by default uses two such fonts: Calibri and Cambria. These fonts are only available in Microsoft Office, and are not freely available for download or use otherwise.
Apertura Designs of Auckland, New Zealand, has issued a small guide to explain how to replace Microsoft proprietary Calibri and Cambria fonts with their open equivalents Carlito and Caladea. The PDF guide is available without restrictions from the following link.