Extensible search engine

1. A computer-implemented method for modifying functionality of a search engine operated on a first server, the first server being operated by a search engine host, comprising:

automatically modifying the functionality of the search engine with a new search function provided by a search function provider, the search function provider operating a second server located remotely from the first server and a user of the search engine, wherein the new search function permits the search engine to search content having an electronic file format that the search engine was previously unable to search; and

making the new search function available to the search engine host by operating the new search function on one of the first server and the second server such that searches using the search engine utilize the new search function.

2. A computer-implemented method for modifying functionality of a search engine, comprising:

receiving a request at a search engine host from a search function proprietor to provide a new search function, wherein the search engine host includes a first server, the first server having the search engine operating thereon, and the search function proprietor includes a second server, the search function proprietor being located remotely from the first server and a user of the search engine;

automatically modifying the functionality of the search engine with the new search function provided by the search function proprietor, wherein the new search function permits the search engine to search content having an electronic file format that the search engine was previously unable to search; and

facilitating use of the new search function with the search engine by operating the new search function on one of the first server and the second server.

3. The computer-implemented method of claim 2 , wherein the search function proprietor acts as a client of the search engine host to provide the new search function.

4. A customizable search system comprising:

a first server hosting a search engine with core functionality; and

an interface configured to facilitate communication between the first server and a second server hosting a new search function not included in the core functionality, wherein the second server is located remotely from the first server and the new search function permits the search engine to search content having an electronic file format that the search engine was previously unable to search.

5. An extensible search system comprising:

a first server hosting a library having a set of search functionality of a search engine, wherein each functionality provides a type of search result in response to a query; and

a receiver configured to receive a request to add a new search functionality to the library from a second server hosting the new search functionality, wherein the new search functionality permits the search engine to search content having an electronic file format that the search engine was previously unable to search.

6. A computer-implemented method for extending a set of search functionality of a search engine to include a new search functionality provided by a search function provider, wherein the search engine operates on a first server, the first server being operated by a search engine host, and wherein the search function provider operates a second server located remotely from the first server and a user of the search engine, comprising:

receiving a request from the search function provider to provide the new search functionality in the set of search functionality of the search engine;

determining, as a function of characteristics of the search engine, any compliance problems associated with including the new search functionality in the set of search functionality of the search engine;

automatically modifying the set of functionality of the search engine based on the determination, wherein the new search functionality permits the search engine to search content having an electronic file format that the search engine was previously unable to search; and

making the new search functionality available to searchers accessing the search engine based on the determination by operating the new search functionality on one of the first server and the second server.

7. The computer-implemented method of claim 6 , wherein operating the new search functionality on the first server comprises:

including the new search functionality in the set of search functionality of the search engine.

8. The computer-implemented method of claim 6 , wherein operating the new search functionality on the second server comprises:

including a link to the new search functionality in the set of search functionality of the search engine, the link effecting communication with the second server, wherein the second server hosts the new search functionality of the search engine.