Since advertising was the primary revenue driver, Yahoo organized its sales team into three categories based on the type of customer served. The field advertising sales channel sold display and search advertising to leading advertisers and agencies. The mid-market channel sold advertising to medium-sized businesses, and the reseller/small business channel sold it to regional and small business advertisers. While Yahoo employed its own sales teams in the United States, it used a combination of internal salespeople and external sales agencies in international markets. The marketing team ensured that the Yahoo! Brand name continued to be widely recognized and drew traffic to the company’s various properties. Yahoo used a combination of organic and acquisition-driven paths to product innovation. It spent $1 billion in internal product development in 2011 (versus $1.1 billion in 2010 and $1.2 billion in 2009), employing a team of software engineers and forming alliances with universities to improve existing products and create new ones.