and software products for the consumer market. The availability of a commercial IPTV product is expected to drive significant growth in MSTV revenue across several geographies. Revenue from existing mobility and embedded devices is expected to increase due to unit volume increases of Windows Mobile software driven by increased market demand for phone-enabled devices and Windows Embedded operating systems. Short product life cycles in product lines such as Windows Mobile software may impact our continuing revenue streams. Xbox 360 console unit costs are expected to decline. 

As we implement our long-term growth strategy, we expect to increase our level of spending in four key areas in fiscal year 2007: increased product costs associated with Xbox consoles; marketing and field sales spending including launch costs; quickening the pace of development in growth areas such as business intelligence, security, management and unified communications (including acquisitions); and increased costs to execute on our online services strategy. While these investments will translate into increased operating expenses in fiscal year 2007, we believe they will help lay the groundwork for future growth and profitability. 

 

 

Operating Expenses 

 

Cost of Revenue 

 

 

Cost of revenue includes manufacturing and distribution costs for products sold and programs licensed, operating costs related to product support service centers and product distribution centers, costs incurred to support and maintain Internet-based products and services, and costs associated with the delivery of consulting services. Cost of revenue in fiscal year 2006 increased mainly due to a $1.64 billion increase in Home and Entertainment as a result of an increase in the number of total Xbox consoles sold and higher Xbox 360 unit costs. Cost of revenue in fiscal year 2005 decreased due to a $363 million decrease in stock-based compensation expense, a $140 million reduction in costs associated with a decrease in the MSN Internet Access subscriber base, and a $169 million reduction in other product costs mainly due to Xbox consoles cost efficiency, partially offset by increased costs in product support and consulting services costs. 

 

Research and Development 

 

 

Research and development expenses include payroll, employee benefits, stock-based compensation expense, and other headcount-related costs associated with product development. Research and development expenses also include third-party development and programming costs, localization costs incurred to translate software for international markets, and the amortization of purchased software code and services content. Research and development costs increased during fiscal year 2006 primarily due to increased development costs associated with new and upcoming offerings such as MSN adCenter, the 2007 Microsoft Office system, Windows Vista, Xbox 360, and corporate research activities. Headcount-related costs increased 3% during fiscal year 2006 reflecting both a 17% increase in headcount and an increase in salaries and benefits for existing headcount, partially offset by a decrease in stock-based compensation expense. Our