How to make user trust our recommender system is a crucial
design goal . Image that if a RS always recommend items that
a user have never seen , so the items will be strange to the user.
In other words , the RS will not be so friendly to the user . So
how to make RS seems that it can understand the user’s psychology
is a very important point. It’s just like that RS play a friend role of the
user . In fact , it has simple way to do this : try to recommend items
that the user have ever seen , then let user feel friendly toward our
systems just like his/her friend . So , accuracy is not enough in designing
a RS , we must consider other factors like HCI perspectives in order to
let users easily control our RS.