4. The computer implemented method of claim 3 , wherein determining a set of potential topic descriptors for the linked content further comprises: comparing the link with one or more search logs obtained from at least one search engine; identifying search queries from the search logs that resulted in search results that included the link; and including the identified search queries as potential topic descriptors in the set of potential topic descriptors.
5. The computer implemented method of claim 4 , wherein selecting a topic descriptor from the set of potential topic descriptors comprises: scoring each potential topic descriptor of the set of potential topic descriptors; and selecting the highest scoring potential topic descriptor as the selected topic descriptor.