1. A computer-implemented method for measuring an efficiency of a social media campaign (campaign) presented on a profile page on a social network, comprising: collecting: searchable activity data which is publicly available on profile pages associated with members of the social network; and private activity data in the social network which is not publicly available from a remote server of the social network using a communication network; extracting, from the searchable activity data, interaction data representing audience feedback on the campaign; assigning a weight to each interaction based on a type of the interaction; calculating an engagement score based on the amount of interactions and the weight associated with each interaction; correlating the searchable activity data and the private activity data to estimate a value for a number of members of the social network reached by the campaign (reach); estimating an amount of money spent in developing the campaign based on the profile page of the campaign; determining an efficiency score of the campaign as a ratio between the amount of money and a number calculated based on the engagement score and the reach.