3. The method of claim 1 , where using the expanded attribute whitelist to identify valid pairings of candidate attributes with candidate values comprises: identifying a plurality of pairings of candidate attributes with candidate values from a second collection of documents, the pairings of candidate attributes with candidate values identified according to a respective structure of one or more of the documents in the second collection; grouping the pairings of candidate attributes with candidate values according to both a particular document in the second collection in which each pairing of candidate attributes with candidate values was identified and the underlying structure in the particular document in the second collection; and determining whether a particular pairing of a candidate attribute with a candidate value identified in the documents of the second collection of documents is in a group with a threshold number of pairings of candidate attributes with candidate values that have an attribute on the expanded attribute whitelist, and if so, including the particular pairing of a candidate attribute with a candidate value in the plurality of valid pairings of candidate attributes with candidate values.
1. A computer-implemented method, comprising: obtaining an initial attribute whitelist, the initial attribute whitelist including one or more initial attributes; processing a first collection of documents, wherein each of the documents has content to be displayed and an underlying structure that defines how the content is to be displayed, to identify a plurality of pairings of candidate attributes with candidate values in the documents, wherein each candidate attribute and each candidate value is content found in the content to be displayed; grouping the candidate attributes into a plurality of groups according to both a particular document in the first collection in which each candidate attribute was identified and the underlying structure in the particular document in the first collection in which each candidate attribute was identified; calculating a score for each unique attribute in the candidate attributes, where the score reflects a number of groups containing both the unique attribute and an attribute on the initial attribute whitelist; generating an expanded attribute whitelist, the expanded attribute whitelist including the initial attributes and each unique attribute having a respective score that satisfies a threshold; and using the expanded attribute whitelist to identify valid pairings of candidate attributes with candidate values.