3. The method of claim 2 , wherein the restriction comprises one of a group consisting of a time associated with the video content, a time associated with the external source, a producer of the video content, a producer of the external source, a popularity of the video content, a popularity of the external source, an owner of the video content, an identity of the user, a genre of the external source, and a genre of the video content.
2. The method of claim 1 , further comprising: determining a restriction based on the segment of closed-caption text; and selecting a subset of external sources from the set of external sources based on the restriction, wherein selecting the external source is from the subset of external sources.