18. The one or more computer-readable storage media of claim 16 , wherein the recommendation is a storage location, and wherein the operations further include storing an attachment to an email in the storage location, and replacing the attachment in the email with a link to the stored attachment.
16. One or more computer-readable storage media storing instructions that, when executed by one or more computing devices, cause the one or more computing devices to perform operations comprising: performing a first process repeatedly, wherein the first process includes: (i)extracting content information corresponding to a new or modified content item from a collection of digital content items to be distributed in a plurality of locations on a network, (ii) normalizing the new or modified content item corresponding to the extracted content information, (iii) sending the normalized content item to a data warehouse, which is a local storage for managing a normalized content item, and (iv) registering keywords extracted from the new or modified content item to the data warehouse; performing a second process repeatedly, wherein the second process includes: (i) examining a new content item of the data warehouse, (ii) generating an index from content information of the new content item, and (iii) updating an index database using the generated index, receiving a query from computing device, wherein the query is automatically generated by a client program of the computing device in response to a user's operation of an application; determining a context of the user associated with the received query; generating an enhanced query by using a registered keyword corresponding to the contents of the query according to the reception of the query; performing a search based on the context of the user and contents of the enhanced query generated by using the registered keyword; generating a recommendation according to a result of the search and an index in the index database; and returning the generated recommendation to the client program of the computing device.