A personalized recommendation is pretty simple in concept. In its most basic form, it just means to present or offer someone only those options for a particular situation that have the highest probability of being chosen by that individual, or in a kind of hands-on sense, presenting merchandise or promotional items that will have the highest probability of being purchased by that type of individual.

These recommendations are characteristically made based on experienced user behavior such as user purchases, page views, clicks, and even items a user has added to a (shopping) cart but perhaps hasn't actually purchased.

These recommendations are not made simply because  they visually coordinate, come from the same collection, or are made by the same manufacturer, and so on.

If you do the research, the most common theme around personalized recommendations is that: