Graphical display advertising places graphical ads alongside content on variety of pages around the Web. From its early beginning in the 1990s, display advertising has grown into a $7 billion industry that supports a big swath of the Web eco-system: from large publishers to niche web sites, allowing for great diversity of sites and content. Targeting has been a key technology that improves the utility of all the participants in the display advertising by providing better audience to the advertiser, more relevant ads to the user and increased revenue to the advertiser. In this talk, I will give a general overview the targeting as an area of computational advertising and then discuss a some case studies of recently reported results in this area. The discussion will include scientifically challenging details about how the computational aspects work.