Sitecore Personalization is being used by most companies when developing a website. For personalization to work, we need to feed in data about the user journey, interactions, activities and so on. Without those data, it will be practically impossible to serve a user with contents that the he or she is interested in.
Below diagram is the high level of the personalization process.
The main process is that when a user visits the site, the application will recommend the user with contents based on different criteria that have been met. The application will receive these data from the Data Analysis and Pattern Discovery.
The analysis and pattern data is obtained from different sources like the user profiles, user journey on the site and user activities, i.e, what the user has been doing on the site.
The recommendation model calculates which contents are relevant to be served to the user based on the data provided by the data analysis and pattern.
The Cold Start Problem
Normally, when you first develop a new website or migrating a website to Sitecore, data about the users’ actions, visits and so on are not available. This is call the Cold Start problem. There is no data in the database for the personalization to work accordingly.
Sitecore has released the Data Exchange Framework. This module facilitates the transfer of data between two systems. So, you can import the data from Google Analytics or other sources that the site was using to store user tracking information to the xDB.
The Hot Start
Hot Start is when you already have all the required information for personalization to work. For example, the site being migrated is already on Sitecore 6 and is being upgraded to Sitecore 8. So, all the data about the users are stored in the Sitecore DMS. It only requires a migration of those data to the xDB and then make use of Sitecore Personalization feature.