Blending search results on online social networks

One or more computer-readable non-transitory storage media embodying software that is operable when executed to:

• receive a search query from a first user of an online social network;
• search a plurality of verticals to identify a plurality of sets of objects in each vertical, respectively, that match the search query, wherein each vertical stores one or more objects of a particular object-type, and wherein each object is associated with the online social network;
• rank, for each set of identified objects in each respective vertical, each identified object in the set of identified objects;
• blend the plurality of sets of identified objects from each vertical to form a set of blended search results comprising a threshold number of identified objects, the blending comprising performing a number of iterations until the set of blended search results comprises at least the threshold number of identified objects, each iteration comprising:
• determining a blender score for each top-ranked identified object in each set of identified objects;
• and
• for the top-ranked identified object having a highest blender score:
• adding the object to the set of blended search results;
• removing the object from its particular set of identified objects;
• and
• promoting a second-ranked identified object from the particular set of identified objects to the top-ranked identified object of the particular set of identified objects;
• and
• send, responsive to the search query, the set of blended search results to the first user for display.

A system comprising:

• one or more processors;
• and a memory coupled to the processors comprising instructions executable by the processors, the processors operable when executing the instructions to:
• receive a search query from a first user of an online social network;
• search a plurality of verticals to identify a plurality of sets of objects in each vertical, respectively, that match the search query, wherein each vertical stores one or more objects of a particular object-type, and wherein each object is associated with the online social network;
• rank, for each set of identified objects in each respective vertical, each identified object in the set of identified objects;
• blend the plurality of sets of identified objects from each vertical to form a set of blended search results comprising a threshold number of identified objects, the blending comprising performing a number of iterations until the set of blended search results comprises at least the threshold number of identified objects, each iteration comprising:
• determining a blender score for each top-ranked identified object in each set of identified objects;
• and
• for the top-ranked identified object having a highest blender score:
• adding the object to the set of blended search results;
• removing the object from its particular set of identified objects;
• and
• promoting a second-ranked identified object from the particular set of identified objects to the top-ranked identified object of the particular set of identified objects;
• and
• send, responsive to the search query, the set of blended search results to the first user for display.