A1. Content-based: this approach gives recommendations based on a particular user’s
feedback. Sights similar to what they liked in the past are recommended (RD5).
A2. Collaborative Filtering: this approach recommends sights that users liked which are
similar to a particular user. This information is based on their previous feedbacks
(RD5 and RD6): Sights that these similar users liked are recommended.
A3. Knowledge-based: this approach recommends sights based on the context; it recommends
sights that are semantically-related to sights this user has visited in the
past (RD2 and RD4). For example, a user receives recommendations about further
beaches after they visited two beaches