Sui generis
In sociology, the "sui generis" is what has been externalized, then internalized in the overall public and becomes a part of society that simply exists in its construct. It is not something that is not thought to have been created, because it is imbedded in everyone's way of thinking and being. Instances include the idea of love, or going to school, or clothing belonging to a specific gender. These examples are "sui generis" for they simply exist in society and are widely accepted without thoughts of where they come from or how they were created.
Professional services networks
Professional service networks are sui generis, and each network is formed for a different reason. Current and potential members are attracted to networks in which they can pursue their own individual objectives. While networks clearly do have things in common, each must be viewed in the context of its uniqueness. A successful network is one that meets the expectations of all of its members.