A search engine optimization system is provided with an on-line social network system. The on-line social network system includes or is in communication with a search engine optimization (SEO) system that is configured to prioritize company keywords (potential search terms) that represent respective people search results pages (PSERPs). The value of a company keyword is expressed as a priority score assigned to that company keyword. The SEO system generates priority scores for different company keywords, using a probabilistic model that takes into account a value expressing how likely the company keyword is to be included in a search query as a search term and/or a value expressing how likely is a search that includes the company keyword as a search term is to produce relevant results, as well as other signals that are indicative of the relative importance of a company represented by the company keyword.