13. A system of ranking candidate curation items, the system comprising: a processor implemented at least partially by hardware; and a non-transitory computer-readable medium communicatively coupled to the processor and having computer-executable instructions stored thereon that are executable by the processor to perform operations comprising: receiving a query; extracting a plurality of items from a plurality of curations; calculating, based on the query, a content similarity measurement for each of the extracted plurality of items; extracting, from each of the extracted plurality of items, a plurality of curation-specific features; calculating one or more curation-specific measurements for each of the extracted plurality of items based on the extracted plurality of curation-specific features, the one or more curation-specific measurements being different than the content similarity measurement; and ranking each of the extracted plurality of items based on both the content similarity measurement and the one or more curation-specific measurements to generate a plurality of curation item results; wherein the one or more curation-specific measurements comprises, for each of the extracted plurality of items, a curation item popularity credit measurement relating to a popularity of a corresponding extracted item; wherein calculating the curation item popularity credit measurement includes calculating a curation popularity credit measurement of each curation in which a corresponding extracted item is included; wherein the curation item popularity credit measurement is calculated according to Σ i=1 CN Curation_Popularity_i/INi, wherein CN is a number of curations that each includes the corresponding extracted item, Curation_popularity_i is the curation popularity credit measurement of a curation i, and INi is a number of items included in the curation i.
13. A system of ranking candidate curation items, the system comprising: a processor implemented at least partially by hardware; and a non-transitory computer-readable medium communicatively coupled to the processor and having computer-executable instructions stored thereon that are executable by the processor to perform operations comprising: receiving a query; extracting a plurality of items from a plurality of curations; calculating, based on the query, a content similarity measurement for each of the extracted plurality of items; extracting, from each of the extracted plurality of items, a plurality of curation-specific features; calculating one or more curation-specific measurements for each of the extracted plurality of items based on the extracted plurality of curation-specific features, the one or more curation-specific measurements being different than the content similarity measurement; and ranking each of the extracted plurality of items based on both the content similarity measurement and the one or more curation-specific measurements to generate a plurality of curation item results; wherein the one or more curation-specific measurements comprises, for each of the extracted plurality of items, a curation item popularity credit measurement relating to a popularity of a corresponding extracted item; wherein calculating the curation item popularity credit measurement includes calculating a curation popularity credit measurement of each curation in which a corresponding extracted item is included; wherein the curation item popularity credit measurement is calculated according to Σ i=1 CN Curation_Popularity_i/INi, wherein CN is a number of curations that each includes the corresponding extracted item, Curation_popularity_i is the curation popularity credit measurement of a curation i, and INi is a number of items included in the curation i. 14. The system of claim 13 , wherein: the curation popularity credit measurement of the curation i is calculated according to Curation_popularity_i=V*View_Score_i+B*Bookmark_Score_i+C*Comment_Score_i; Curation_popularity_i is the curation popularity credit measurement of curation i; V, B, and C are constants where V+B+C=1; View_Score i is calculated based on a number of views of the curation i; Bookmark_Score_i is calculated based on a number of bookmarks to the curation i; and Comment_Score_i is calculated based on a number of comments to the curation i.