in marketing expense, we view free shipping offers and Amazon Prime as effective worldwide marketing tools, and intend to continue offering them indefinitely. 

Technology and Content 

We seek to efficiently invest in several areas of technology and content including seller platforms, web services, digital initiatives, and expansion of new and existing product categories, as well as technology infrastructure so that we can continue to enhance the customer experience, improve our process efficiency and support our infrastructure web services. See “Overview” for a discussion of how management views advances in technology and the importance of innovation. We expect spending in technology and content to increase over time as we continue to add employees to our staff and add technology infrastructure. 

For the years ended 2009, 2008, and 2007, we capitalized $187 million, $187 million, and $129 million of costs associated with internal- use software and website development. Amortization of previously capitalized amounts was $172 million, $143 million, and $116 million for 2009, 2008, and 2007. 

A significant majority of our technology costs are incurred in the U.S. and most of them are allocated to our North America segment. 

General and Administrative 

The increase in general and administrative costs in absolute dollars in 2009 compared to 2008 and 2007 is primarily due to increases in payroll and related expenses, and professional service fees. 

Stock-Based Compensation 

Stock-based compensation was $341 million, $275 million, and $185 million during 2009, 2008, and 2007. The increase in stock-based compensation in 2009 compared to 2008 is primarily attributable to a decrease in our estimated forfeiture rate. The increase in stock-based compensation in 2008 compared to 2007 was primarily attributable to an increase in total stock-based compensation value granted to our employees. 

Other Operating Expense (Income)

Other operating expense (income), net, was $102 million, $(24) million and $9 million during 2009, 2008 and 2007. The increase in other operating expense in 2009 is primarily attributable to the $51 million Toysrus.com LLC settlement, and increased amortization expense on acquired intangibles. In 2008, we recognized a $53 million noncash gain on the sale of our European DVD rental assets. 

Interest Income and Expense 

Our interest income was $37 million, $83 million, and $90 million during 2009, 2008, and 2007. We generally invest our excess cash in investment grade short- to intermediate-term fixed income securities and AAA-rated money market funds. Our interest income corresponds with the average balance of invested funds and the prevailing rates we are earning on them, which vary depending on the geographies and currencies in which they are invested. 

The primary component of our net interest expense is the interest we incur on our long-term debt instruments. Interest expense was $34 million, $71 million, and $77 million, in 2009, 2008, and 2007 with the decline primarily relating to principal reductions of $319 million in 2009 and $899 million in 2008. 

Our long-term debt was $109 million and $409 million at December