Communicating information between clients of a data repository that have deposited identical data items

A method for communicating information between clients of a data repository that have independently deposited data items with identical content, the method comprising:

• depositing a plurality of data items into the data repository in response to requests by a plurality of client programs, with deposits of data items that have identical content identified by the data repository and this identification used to conserve storage space;
• depositing a first data item in the data repository in response to a request by a first client program to deposit the first data item, the depositing of the first data item comprising:
• ensuring that a stored data item identical to the first data item exists in the data respository, and
• creating a first credential that allows the first client program to retrieve the stored data item in the future;
• assigning an expiration time to the stored data item, before which time both modification and deletion are prohibited;
• storing an informational tag associated with the stored data item, in response to a request by the first client program to tag the first data item with specified information;
• independently depositing a second data item in the data repository, which is identical in content to the first data item, in response to a request by a second client program to deposit the second data item, the depositing of the second data item comprising:
• discovering that the second data item is identical to the stored data item, and
• creating a second credential that allows the second client program to retrieve the stored data item in the future;
• and
• retrieving the informational tag stored by the first client program, in response to a request by the second client program to retrieve informational tags that are associated with the stored data item;
• wherein the first client program and the second client program are independent programs that do not communicate directly with each other;
• wherein the first client program and the second client program each separately communicate with the data repository;
• wherein the retrieving step communicates the specified information to the second client program;
• wherein the data repository does not restrict which types of content can be tagged;
• and
• wherein the content and purpose of the informational tag stored by the first client program are defined by a user of the data repository who is associated with the first client program.