1. A method, comprising: storing, via a computing device, in a directory: collaborative information; a plurality of common message data models, each of the common message data models for use in forming annotated messages comprising links and metadata extracted from the collaborative information; and a plurality of common primitive message exchange sequences, each common primitive message exchange sequence comprising a combination of at least two common message data models, each common primitive message exchange sequence for use in an exchange of a sequence of annotated messages, the plurality of common primitive message exchange sequences comprising a first common primitive message exchange sequence comprising a first and a second common message data model; initiating, via a computer system configured for on-demand business collaboration, the first common primitive message exchange sequence by forming and sending a first annotated message based on the first common message data model, the first annotated message comprising links and metadata extracted from the collaborative information stored in the directory; and receiving, in response to the first annotated message, a second annotated message based on the second common message data model.