Document scoring based on link-based criteria

1. A computer-implemented method, comprising:

receiving, by one or more server devices, history data for a document, the history data comprising an appearance date for each of a plurality of links to the document;

determining, by one or more processors of the one or more server devices and from the history data, that there has been a decrease in a rate or quantity of appearances of new links that point to the document over time, and then classifying the document as stale,

the determining that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time comprising:

comparing an oldest appearance date of the appearance dates, of the links to the document, to an oldest appearance date of the appearance dates of a group of newest links to the document, each link in the group of newest links to the document having an appearance date that is within a percentage of most recent appearance dates of the links to the document;

based on classifying the document as stale, decreasing, by the one or more processors of the one or more server devices, an initial score for the document, resulting in an altered score; and

ranking, by the one or more processors of the one or more server devices, the document with regard to at least one other document based on the altered score.

2. The method of claim 1 , further comprising:

receiving a search query, where the document and the at least one other document are responsive to the search query; and

presenting the document and the at least one other document according to the ranking.

3. The method of claim 1 , where the appearance date for a particular link, of the plurality of links, is a date that a search engine web crawler first crawls a document that includes the particular link.

4. The method of claim 1 , where determining that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time further comprises comparing a quantity of appearances of new links to the document during a recent pre-defined time period to a total quantity of appearances of new links to the document.

5. The method of claim 4 , where the recent pre-defined time period is a pre-defined number of most-recent days.

6. The method of claim 1 , where the history data is first history data, and where the document is a first document, the method further comprising:

receiving second history data for a second document, the second history data comprising an appearance date for each of a plurality of links to the second document;

determining, from the second history data, that there has been an increase in a rate or quantity of appearances of new links that point to the second document over time;

classifying the second document as fresh based on determining that there has been an increase in the rate or quantity of appearances of new links that point to the second document over time; and

based on classifying the second document as fresh, increasing an initial score for the second document.

7. The method of claim 1 , where the history data is first history data, and where the document is a first document, the method further comprising:

receiving second history data for a second document, the second history data comprising a disappearance date for each of a plurality of links to the second document;

determining, based on the second history data, that there has been a decrease in a rate or quantity of disappearances of links that point to the second document over time;

classifying the second document as stale based on determining that there has been a decrease in the rate or quantity of disappearances of links that point to the second document over time; and

decreasing an initial score for the second document based on classifying the second document as stale.

8. A system, comprising:

one or more processing devices to:

receive history data for a document, the history data comprising an appearance date for each of a plurality of links to the document;

determine, from the history data, that there has been a decrease in a rate or quantity of appearances of new links that point to the document over time, and then classify the document as stale,

the one or more processing devices, when determining that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time, further being to:

compare an oldest appearance date, of the appearance dates of the links to the document, to an oldest appearance date of the appearance dates of a group of newest links to the document, each link in the group of newest links to the document having an appearance date that is within a percentage of most recent appearance dates of the links to the document;

decrease, based on classifying the document as stale, an initial score for the document, resulting in an altered score; and

rank the document with regard to at least one other document based on the altered score.

9. The system of claim 8 , where the one or more processing devices are further to:

receive a search query, where the document and the at least one other document are responsive to the search query; and

present the document and the at least one other document according to the ranking.

10. The system of claim 8 , where the appearance date for a particular link, of the plurality of links, is a date that a search engine web crawler first crawls a document that includes the particular link.

11. The system of claim 8 , where when determining that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time, the one or more processing devices are further to compare a quantity of appearances of new links to the document during a recent pre-defined time period to a total quantity of appearances of new links to the document.

12. The system of claim 11 , where the recent pre-defined time period is a pre-defined number of most-recent days.

13. The system of claim 8 , where the history data is first history data, and where the document is a first document, where the one or more processing devices are further to:

receive second history data for a second document, the second history data comprising an appearance date for each of a plurality of links to the second document;

determine, from the second history data, that there has been an increase in a rate or quantity of appearances of new links that point to the second document over time;

classify the second document as fresh based on determining that there has been an increase in the rate or quantity of appearances of new links that point to the second document over time; and

increase an initial score for the second document in response to classifying the second document as fresh.

14. The system of claim 8 , where the history data is first history data, and where the document is a first document, where the one or more processing devices are further to:

receive second history data for a second document, the second history data comprising a disappearance date for each of a plurality of links to the second document;

determine, based on the second history data, that there has been a decrease in a rate or quantity of disappearances of links that point to the second document over time;

classify the second document as stale based on determining that there has been a decrease in the rate or quantity of disappearances of links that point to the second document over time; and

decrease an initial score for the second document based on classifying the second document as stale.

15. A non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions comprising:

one or more instructions to receive history data for a document, the history data comprising an appearance date for each of a plurality of links to document;

one or more instructions to determine, from the history data, that there has been a decrease in a rate or quantity of appearances of new links that point to the document over time, and then classify the document as stale,

the one or more instructions to determine that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time, including:

one or more instructions to compare an oldest appearance date, of the appearance dates of the links to the document, to an oldest appearance date of the appearance dates of a group of newest links to the document, each link in the group of newest links to the document having an appearance date that is within a percentage of most recent appearance dates of the links to the document;

one or more instructions to decrease, based on classifying the document as stale, an initial score for the document, resulting in an altered score; and

one or more instructions to rank the document with regard to at least one other document based on the altered score.

16. The non-transitory computer-readable storage medium of claim 15 , where the computer-readable instructions further comprise:

one or more instructions to receive a search query, where the document and the at least one other document are responsive to the search query; and

one or more instructions to present the document and the at least one other document according to the ranking.

17. The non-transitory computer-readable storage medium of claim 15 , where the appearance date for a particular link, of the plurality of links, is a date that a search engine web crawler first crawls a document that includes the particular link.

18. The non-transitory computer-readable storage medium of claim 15 , where the one or more instructions to determine that there has been a decrease in the rate or quantity of appearances of new links that point to the document over time further include one or more instructions to compare a quantity of appearances of new links to the document during a recent pre-defined time period to a total quantity of appearances of new links to the document.

19. The non-transitory computer-readable storage medium of claim 15 , where the history data is first history data, and where the document is a first document, where the computer-readable instructions further comprise:

one or more instructions to receive second history data for a second document, the second history data comprising an appearance date for each of a plurality of links to the second document;

one or more instructions to determine, from the second history data, that there has been an increase in a rate or quantity of appearances of new links that point to the second document over time;

one or more instructions to classify the second document as fresh based on determining that there has been an increase in the rate or quantity of appearances of new links that point to the second document over time; and

one or more instructions to increase an initial score for the second document based on classifying the second document as fresh.

20. The non-transitory computer-readable storage medium of claim 15 , where the history data is first history data, and where the document is a first document, where the computer-readable instructions further comprise:

one or more instructions to receive second history data for a second document, the second history data comprising a disappearance date for each of a plurality of links to the second document;

one or more instructions to determine, based on the second history data, that there has been a decrease in a rate or quantity of disappearances of links that point to the second document over time;

one or more instructions to classify the second document as stale based on determining that there has been a decrease in the rate or quantity of disappearances of links that point to the second document over time; and

one or more instructions to decrease an initial score for the second document based on classifying the second document as stale.