This paper addresses adult lifelong learners, i.e., persons interested in learning or compelled to learn during their working life but not able to, or not interested in participating in formal learning. These learners are motivated and self-aware enough to self-direct their learning, are presumed to be novices with respect to the needed knowledge and have a limited technological uptake. This paper will outline their main differences from regular learners, in particular, for the use of social media to improve learning skills. The reference pedagogical model is andragogy. A Service-Oriented Architecture, named Personal Knowledge Space (PKS), is proposed to support our lifelong learners in selecting, organizing, and retrieving information; in streamlining interaction processes among learners, services and resources and finally in empowering control and trust of personal relationships born during the learning processes. The PKS is mainly based on the exploitation of semantic tools (ontologies) and web services. Use cases describing the PKS architecture and one scenario of PKS use are presented.