Personalization or personalisation (see spelling differences) is tailoring a consumer product, electronic or written medium to a user based on personal details or characteristics they provide. More recently, it has especially been applied in the context of the World Wide Web.

Web pages

Web pages are personalized based on the interests of an individual. Personalization implies that the changes are based on implicit data, such as items purchased or pages viewed. The term customization is used instead when the site only uses explicit data such as ratings or preferences.

On an intranet or B2E Enterprise Web portals, personalization is often based on user attributes such as department, functional area, or role. The term customization in this context refers to the ability of users to modify the page layout or specify what content should be displayed.

There are two categories of personalizations:

1. Rule-based
2. Content-based

Web personalization models include rules-based filtering, based on "if this, then that" rules processing, and collaborative filtering, which serves relevant material to customers by combining their own personal preferences with the preferences of like-minded others. Collaborative filtering works well for books, music, video, etc. However, it does not work well for a number of categories such as apparel, jewelry, cosmetics, etc. Recently, another method, Prediction Based on Benefit is proposed for products with complex attributes such as apparel.

Many companies offer services for web recommendation and email recommendation that are based on personalization or anonymously collected user behaviors.

Personalisation is also being considered for use in less overtly commercial applications to improve the user experience online .

Search engines

Google is the first of the "Big Three" search engines to introduce personalized results on a massive scale. Weighing a number of factors including but not limited to user history, bookmarks, community behaviour and site click-through rate and stickiness, Google is providing results that are specific to what they believe you are searching for.

Currently this service is only available to those who are logged into their Google account .

Amazon.com has been the early adopter of personalization technology to recommend products to shoppers on its site, based upon their previous purchases. Amazon makes extensive use of Collaborative Filtering in its personalization technology.

Profiling models of personalization

Personalization does not necessarily need to be based on individual user accounts (as is conventional); it can also be based on region or language (see localization) or browser.

Print media

main: Mail merge

In print media, ranging from magazines to promotional publications, personalization uses databases of individual recipients' information. Not only does the written document address itself by name to the reader, but the advertising is targeted to the recipient's demographics or interests using fields within the database, such as "first name", "last name", "company", etc.