Products and services recommendation systems in e-commerce. Recommendation methods, algorithms, and measures of their effectiveness

The article concerns products and services recommendation systems in ecommerce which have become increasingly important for both consumers and retailers. The methods used for the recommendation of products and services, as well as the algorithms used to implement them, are presented in the article. Particular attention was paid to the problems of testing the suitability of algorithms, along with the effectiveness measures of the applications of the methods and algorithms