The series currently has seven major releases and four expansions on gaming consoles. There are spin-offs for Windows and Macintoshsystems, mobile phones, the Nintendo DS, and an arcade game. The Guitar Hero franchise was a primary brand during the emergence of the popularity of rhythm games as a cultural phenomenon in North America. Such games have been utilized as a learning and development tool for medical purposes. The first game in the series was considered by several journalists to be one of the most influential video games of the first decade of the 21st century. The series has sold more than 25 million units worldwide, earning US$2 billion at retail, claimed by Activision to be the 3rd largest game franchise after the Mario and Madden NFL franchises; the third main title of the series, Guitar Hero III: Legends of Rock is also claimed by Activision to be the first single video game title to exceed $1 billion in sales. Despite early success, the series, along with the overall rhythm game genre, suffered from poor sales starting in 2009, and in early February 2011, Activision disbanded further development of the series, though later clarified that the series is on hiatus for 2011.