9. A computer program product comprising a non-transitory computer useable medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to: identify a channel category of a channel for a user based on one of a historical trend and a user activity; receive a request to customize a stream of content for the channel category; responsive to the request to customize, query new content items based on the channel category and a channel attribute; receive candidate content items that include the channel category and the channel attribute; determine a user-independent score for each of the candidate content items to approximate popularity of each candidate content item within the stream of content that produced it; compute a global score for each of the candidate content items by normalizing the user-independent score for each candidate content item across a plurality of streams of content, the global score identifying a popularity of each candidate content item within the plurality of streams of content; customize the stream of content for the channel by adding the candidate content items to the stream of content based on the global score of each candidate content item; and provide the customized stream of content.
9. A computer program product comprising a non-transitory computer useable medium including a computer readable program, wherein the computer readable program when executed on a computer causes the computer to: identify a channel category of a channel for a user based on one of a historical trend and a user activity; receive a request to customize a stream of content for the channel category; responsive to the request to customize, query new content items based on the channel category and a channel attribute; receive candidate content items that include the channel category and the channel attribute; determine a user-independent score for each of the candidate content items to approximate popularity of each candidate content item within the stream of content that produced it; compute a global score for each of the candidate content items by normalizing the user-independent score for each candidate content item across a plurality of streams of content, the global score identifying a popularity of each candidate content item within the plurality of streams of content; customize the stream of content for the channel by adding the candidate content items to the stream of content based on the global score of each candidate content item; and provide the customized stream of content. 11. The computer program product of claim 9 , wherein the historical trend is one of an increase in a number of the new content items for a content category and an increase in a number of times one of the new content items is accessed.