External referencing by portable program modules

1. A computer-implemented method, comprising:

obtaining identity information, with a portable program module, for a source of a webpage associated with a container document, the portable program module located in the container document;

submitting, by the portable program module located in the container documents, the identity information to a concept server storing keywords associated with the container document;

receiving, by the portable program module located in the container document and from the concept server, in response to the submitted identity information, the keywords associated with the container document;

selecting, by the portable program module located in the container document, a subset of the keywords received from the concept server based at least on one or more criteria specified by an author of the portable program module;

submitting, by the portable program module located in the container document, a query to an item search server related to the subset of the keywords selected by the portable program module; and

receiving, at the portable program module located in the container document, advertisements responsive to the query from the item search server for display.

2. The method of claim 1 , wherein the advertisements are advertisements for on-line auctions.

3. The method of claim 1 , further comprising displaying the advertisements within the container document, wherein the advertisements include one or more hyperlinks.

4. The method of claim 3 , further comprising receiving a selection of one of the one or more hyperlinks and causing a web page associated with the hyperlink to be displayed.

5. The method of claim 3 , wherein the hyperlink includes a query for return of content that changes in real time.

6. The method of claim 1 , further comprising formatting the advertisements for the display.

7. The method of claim 1 , wherein the identity information for a source of a webpage comprises a URL associated with the container document.

8. The method of claim 1 , wherein the identity information associated with the container document includes one or more words representing concepts in text on the container document.

9. The method of claim 1 , further comprising:

determining that an inventory associated with one or more products advertised through the container document has become exhausted, then, before obtaining the identity information, invoking the portable program module.

10. The method of claim 1 , wherein submitting, by the portable program module, the query to an item search server comprises inserting the subset of the keywords received from the container document as arguments of the query.

11. The method of claim 10 , further comprising determining, by the portable program module located in the container document, that the subset of the keywords received from the container document will obtain a result from the item search server.

12. The method of claim 1 , further comprising providing, by the portable program module, the advertisements responsive to the query from the item search server.

13. The method of claim 1 , further comprising selecting, by the portable program module located in the container document, the item search server from among multiple item search servers based upon the subset of the keywords selected by the portable program module.

14. A system, comprising:

one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:

obtaining identity information, with a portable program module, for a source of a webpage associated with a container document, the portable program module located in the container document;

submitting, by the portable program module located in the container document, the identity information to a concept server storing keywords associated with the container document;

receiving, by the portable program module located on the container document and from the concept server, in response to the submitted identity information, the keywords associated with the container document;

selecting, by the portable program module located in the container document, a subset of the keywords received from the concept server based at least on one or more criteria specified by an author of the portable program module;

submitting, by the portable program module located in the container document, a query to an item search server related to the subset of the keywords selected by the portable program module; and

receiving, at the portable program module located in the container document, advertisements responsive to the query from the item search server for display.

15. The system of claim 14 , wherein the advertisements are advertisements for on-line auctions.

16. The system of claim 14 , further comprising displaying the advertisements within the container document, wherein the advertisements include one or more hyperlinks.

17. The system of claim 16 , further comprising receiving a selection of one of the one or more hyperlinks and causing a web page associated with the hyperlink to be displayed.

18. The system of claim 16 , wherein the hyperlink includes a query for return of content that changes in real time.

19. The system of claim 14 , further comprising formatting the advertisements for the display.

20. The system of claim 14 , wherein the identity information for a source of a webpage comprises a URL associated with the container document.

21. The system of claim 14 , wherein the identity information associated with the container document includes one or more words representing concepts in text on the container document.

22. A non-transitory computer-readable medium storing software comprising instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:

obtaining identity information, with a portable program module, for a source of a webpage associated with a container document, the portable program module located in the container document;

submitting, by the portable program module located in the container document, the identity information to a concept server storing keywords associated with the container document;

receiving, by the portable program module located on the container document and from the concept server, in response to the submitted identity information, the keywords associated with the container document;

selecting, by the portable program module located in the container document, a subset of the keywords received from the concept server based at least on one or more criteria specified by an author of the portable program module;

submitting, by the portable program module located in the container document, a query to an item search server related to the subset of the keywords selected by the portable program module; and

receiving, at the portable program module located in the container document, advertisements responsive to the query from the item search server for display.

23. The medium of claim 22 , wherein the advertisements are advertisements for on-line auctions.

24. The medium of claim 22 , wherein the operations further comprise displaying the advertisements within the container document, wherein the advertisements include one or more hyperlinks.

25. The medium of claim 24 , wherein the operations further comprise receiving a selection of one of the one or more hyperlinks and causing a web page associated with the hyperlink to be displayed.

26. The medium of claim 24 , wherein the hyperlink includes a query for return of content that changes in real time.

27. The medium of claim 22 , wherein the operations further comprise formatting the advertisements for the display.

28. The medium of claim 22 , wherein the identity information for a source of a webpage comprises a URL associated with the container document.

29. The medium of claim 22 , wherein the identity information associated with the container document includes one or more words representing concepts in text on the container document.