Social media is achieving an increasing importance as a channel for gathering information about products and services. Brands are developing its presence in social networking sites to meet brand awareness, engagement and word of mouth. In this context, the analysis of the factors that are conditioning consumer interaction with branded content becomes a matter of interest. This paper aims to shed light on those factors that are expected to impact on Facebook branded post popularity. A conceptual model is developed to reflect the influence of the content's richness and time frame on the number of comments and likes. An empirical analysis using multiple linear regressions is conducted based on 164 Facebook posts gathered from the fan pages of 5 Spanish travel agencies. Results suggest that the richness of the content (inclusions of images and videos) raises the impact of the post in terms of likes. On the other hand, using images and a proper publication time are significantly influencing the number of comments, whereas the use of links may decrease this metric. This study empirically contributes to the existing literature on the management of marketing strategies for consumer engagement in social networking sites.