13. The system of claim 12 , including further instructions, which, when processed by the at least one processor, cause the at least one processor to determine that the reputation score for the seller of the first item offered via the first item listing exceeds the threshold score, and in response to the determination, to increase the initial ranking score with the adjustment factor to reflect a promotion for the first item listing, the promotion resulting in a higher probability that the first item listing will be presented in the search results page in a position higher than other item listings being offered by sellers who have reputation scores that are less than the threshold score.
12. The system of claim 9 , wherein the initial ranking score associated with an item listing is to be adjusted when a seller of an item offered via the item listing has a reputation score that exceeds a threshold score.