One-to-many may refer to:

Fat link, a one-to-many page link in hypertext
Multivalued function, a one-to-many function in mathematics
One-to-many (data model), a type of relationship and cardinality in systems analysis
Point-to-multipoint communication, communication which has a one-to-many relationship.

The many-to-many communication paradigm[1] is one of three major Internet computing paradigms, characterized by multiple users contributing and receiving information, with the information elements often interlinked across different websites. Developments such as file sharing, blogs, Wikis, and tagging are media forms that reflect this paradigm; these contrast with both the one-to-one (characterized by e-mail, FTP, and Telnet) and one-to-many (characterized by websites) paradigms.

With the evolution to the full "many-to-many" computing paradigm, people can input and receive information to and from the Internet; they will be able to connect and communicate dynamically within a flexibly formed scope; there will be no artificial boundary between information and communication tools, and the definition of "many" will go well beyond people to include entities such as organizations, products, processes, events, and concepts.