Abstract: A method of suggesting replacements for unavailable web pages is performed at a server system separate from a client system. A web page is identified. For documents in a collection of web pages, respective overlaps of content in the web page and the documents are determined based on stored information about content in the web page and the documents. One or more of the documents that have overlaps that satisfy a first criterion are selected. A request for a replacement for the web page is received from the client system and replacement web page information is provided to the client system. The replacement web page information is selected from the set consisting of A) one or more links to the one or more selected documents, B) a redirect to one of the one or more selected documents, and C) one of the one or more selected documents.

Abstract: Methods, systems, and apparatus, including computer program products for identifying original content. In one aspect a method is described that includes deriving a plurality of content pieces from a collection of documents, each content piece occurring in one or more documents in the collection of documents. Each document in the collection of documents is associated with a time and an author. A first document in the collection of documents is identified, the identified first document being the earliest document containing an occurrence of a first piece of content. A first author associated with the first document is ranked based on a number of documents that contain at least one occurrence of the content piece and that are associated with an author other than the first author.

Abstract: Discovering spam merchants using product feed comparison comprises a merchant signature computed by a comparison system using the offer data submitted by a merchant. The merchant submits a file to the comparison system for use on a product comparison website. The comparison system processes the file and calculates a merchant signature by parsing a specific feature common to all offers. The comparison system assigns a data value to each of the specific features included in each of the offers and generates a string of assigned data values. The comparison system executes a hash algorithm for the string of data values to obtain the merchant signature. The merchant signature is compared with the signatures of known spam merchants and if the merchant signature is within a predefined threshold of known spam merchant signatures, the merchant is rejected and the signature is marked as a spam merchant.