A method of providing targeted advertising includes an electronic commerce site that receives a request from a user for a webpage. The electronic commerce site determines an identifier, such as email address, for the user. The electronic commerce site encodes the identifier in a request, such as a universal resource locater (URL), associated with an advertisement. The electronic commerce site embeds the advertisement in the requested webpage and sends the webpage to the user. When an advertising service receives the URL from the user, the advertising service sends a query to a social networking site. The query includes the identifier. Upon receiving preference information for the user from the social networking site in response to query, the advertising service uses the preference information to determine products of interest to the user. The advertising service sends a webpage to the user. The webpage from the advertising service includes information on the products of interest.