1. A method comprising: providing an online advertisement linked to content; obtaining a macro-context vector specifying classification of the content within a domain corresponding to a semantic space; obtaining a personalization vector quantifying the affinity of at least one aspect of a user for a plurality of domains; selecting, by the user, the online advertisement; and multiplying, by a processing element, the personalization vector and the macro-context vector to obtain a match value quantifying the similarity between the personalization vector and the macro-context vector.