11. A non-transitory computer readable medium comprising instructions that when executed by a processor cause the processor to: receive a request for a cover page of a digital magazine from a digital magazine server user, the cover page including information identifying a plurality of groups of content items; determine the digital magazine server user is eligible to receive a specified group of content items based at least in part on historical information describing the user's interactions with the digital magazine server during a specified threshold time interval; selecting the specified group of content items in response to the determination; identify a plurality of candidate feeds of content items to include in the specified group of content items, the plurality of candidate feeds including the specified group; retrieve a plurality of candidate content items from the plurality of candidate feeds; sort the retrieved candidate content items into a plurality of clusters based at least in part on a common topic associated with elements of the retrieved content items; for each content item in a cluster, scoring the sorted content item based on a measure of similarity between the content item and other content items in the cluster; rank scored content items in each cluster based on the scoring; select at least one scored content item from each of the plurality of clusters having a threshold position in the ranking; include the at least one scored content item selected from each of the plurality of clusters in the specified group of content items; and generate the cover page including the specified group of content items and information describing additional content items for display to the digital magazine server user, the specified group of content items included in a specific location within the cover page relative to the additional content items included in the cover page, the specific location within the cover page determined by the digital magazine server based on prior interactions by digital magazine server users with content included in various locations within previously presented cover pages.
11. A non-transitory computer readable medium comprising instructions that when executed by a processor cause the processor to: receive a request for a cover page of a digital magazine from a digital magazine server user, the cover page including information identifying a plurality of groups of content items; determine the digital magazine server user is eligible to receive a specified group of content items based at least in part on historical information describing the user's interactions with the digital magazine server during a specified threshold time interval; selecting the specified group of content items in response to the determination; identify a plurality of candidate feeds of content items to include in the specified group of content items, the plurality of candidate feeds including the specified group; retrieve a plurality of candidate content items from the plurality of candidate feeds; sort the retrieved candidate content items into a plurality of clusters based at least in part on a common topic associated with elements of the retrieved content items; for each content item in a cluster, scoring the sorted content item based on a measure of similarity between the content item and other content items in the cluster; rank scored content items in each cluster based on the scoring; select at least one scored content item from each of the plurality of clusters having a threshold position in the ranking; include the at least one scored content item selected from each of the plurality of clusters in the specified group of content items; and generate the cover page including the specified group of content items and information describing additional content items for display to the digital magazine server user, the specified group of content items included in a specific location within the cover page relative to the additional content items included in the cover page, the specific location within the cover page determined by the digital magazine server based on prior interactions by digital magazine server users with content included in various locations within previously presented cover pages. 18. The non-transitory computer readable medium of claim 11 , wherein instructions that cause the processor to score the sorted content item further comprise instructions that cause the processor to score the sorted content item based on a weight associated with a connection between the digital magazine server user and the content item.