  When a new user just signs up on a website, we usually have no information
about him/her, i.e. no interaction with items, no user profile and no social
links with other users. Under such circumstances, we still expect our
recommender systems could attract the users at the first time so that the users
decide to stay on the website and become active users. This problem falls into
new user cold-start category and it is crucial to the development and even
survival of a company. Existing works on user cold-start recommendation either
require additional user efforts, e.g. setting up an interview process, or make
use of side information [10] such as user demographics, locations, social
relations, etc. However, users may not be willing to take the interview and
side information on cold-start users is usually not available. Therefore, we
consider a pure cold-start scenario where neither interaction nor side
information is available and no user effort is required. Studying this setting
is also important for the initialization of other cold-start solutions, such as
initializing the first few questions of an interview.
