I. Introduction
Nowadays, Science knowledge may have a very short life span. An aftermath of this trend is the need for constant renewal of knowledge after formal education. The process is known as lifelong learning. As the state of the art information is placed on Internet, it makes Internet an inevitable learning resource. According to a few studies concerning learning in adult age, between 70% and 80% of learning is informal [1], [2], mostly managed by learners, it is intentional and self-directed.