Customization and personalization might seem interchangeable, but there is a fundamental difference in how they work.
Customization is the changes users make to an application or operating system. For example, users might move items around an interface according to their priorities, select topics of interest, altering colors or other factors related to the visual design of an interface. Naturally, customization requires considerable effort on the part of the user.
In contrast, personalization is something applications do for users to enhance their experience by tailoring a navigation, search results, content, or notifications to users’ unique needs. It leverages what the system knows about the user or user groups. Personalization requires no effort on the part of the user.
• Customization works well under the assumption that users know best what their goals and needs are.
• Personalization can work well if users do not know exactly what they need and must filter through a large information space.
• Customization and personalization both enhance an already good experience on a site. They don't fix a poor one.