The most successful social services (delicious, Flickr and YouTube) are not initially thought as social networks, but as specific services for small groups of users. For example, the main motivation for joining Flickr is not because it is the best way to build a social network of photos, but because it is the best way to save and share photos with friends. However, after making use of basic core capabilities, users discover the value-added features of Flickr that help to meet other people with the same interests.

Thus, the key element for effective social network construction is to provide a set of contents, tools and services that perfectly suits user needs and tastes. This is the reason for considering the PLE as an excellent start point in order to build a social network.

A PLE is composed of a set of customized applications on the client side of which most will exchange information with server side applications. Thus, if a PLE becomes essential for the daily work of a user, the data flow between client and server side applications will allow the automatic feed of the social networks to which the users belongs to.