Ah, here's an article you can read:
Games-time volunteers mainly serve venues (including competition venues, training venues and non-competition venues). Services mainly include protocol, translation, security, medical care, liaison, etc. The recruitment of Olympic volunteers ended in May 2008.
Urban volunteers are mainly volunteer service stations for the Beijing Olympic Games, which are located around the Olympic venues and in key urban areas such as important transportation hubs, commercial outlets, tourist attractions, medical institutions, hotels and cultural activities places, providing voluntary services such as information consultation, language translation and emergency assistance. At the end of June 2008, the registration of urban volunteers ended, and the number of applicants reached 2.07 million.
Social volunteers are volunteers who perform voluntary services such as maintaining order, advocating civilization, beautifying the environment and helping the poor in public places during the Games-time, covering all volunteers except Games-time volunteers and city volunteers.
In addition, during the Olympic and Paralympic Games, 200,000 cheerleaders will drive the audience to interact and create a civilized and warm atmosphere.