7. A computing system comprising one or more computing devices, said computing system programmed to implement a process for enabling users to share and locate content clippings, said process comprising: receiving, via an electronic communication network from user computing devices of a plurality of users, a plurality of content portions and corresponding bibliography citations from clipping modules that run on the user computing devices of the plurality of users, the content portions including metadata tags that describe the content portions, said metadata tags including user-generated metadata tags entered by users using a user interface of the clipping modules, wherein the content portions include user-selected clips of web pages, and the bibliographic citations include auto-generated citations generated at least partly by automatically scanning the web pages for attributes to include in the citations; storing the received content portions and bibliography citations in data storage, said data storage being separate from storage of the user computing devices; and using the metadata tags to automatically identify, among the content portions stored in the data storage, uploaded content portions that are related to each other.
10. The computing system of claim 7 , wherein the process further comprises selectively exposing particular ones of said content portions to subsets of the users based on social networking connections formed between the users.