Online advertising has become a popular method for companies to market their products and services to potential customers. The methods used by conventional web advertisement systems to decide on which advertisements to display to users in a real-time bidding environment generally do not consider the latent interests of users and as such it is difficult for advertisers to target and acquire new customers with potential interest in the product. Therefore, we proposed the development of a recommender system which could recommend advertisements to users based on their latent interests. In this paper, we outline two experiment studies related to the development of this system. The first study was carried out to examine the effect of using a long and short browsing history acquisition period to train the user model and predict user interests. The results suggested that a longer browsing history acquisition period did not necessarily result in better predictive performance. The second study examined the use of a categorized web browsing history to predict user interest. The results showed the accuracy of the classifiers increased when website categories were used instead of Fully Qualified Domain Names.