Problem based learning (PBL) is an educational method in which the learning is made by solving specific problems, using both interaction and individual study, and supervised by a teacher – called facilitator. In medical area, a PBL session will start from a real life situation, most of the time a clinical scenario, which is read and, under the supervision of the facilitator, the students identify the unknown topics that must be understand and learned. After that, the students have a period of time for individual study. The group is rejoining and, applying the new learned knowledge, the problem is solved. 
PBL was used for the first time in medical education in late 60’s, at McMaster University in Canada. The reason for implementing this new method was the statement that the process for diagnosing a patient is based by a combination of clinical reasoning and specific knowledge in different domains. By learning specific disciplines (anatomy, physiology, neurology, pharmacology) as individual ones, the students fail to integrate the knowledge in clinical context and have difficulties in applying in the practice. The advance of the medical science and the rapid changing of the specific approaches was also an argument for the use of the PBL as educational method in medical education. [2,3]
The validity of this method in medical education was studied by Albanese and Mitchell in a meta-analysis which contains 20 studies evaluating PBL results . The conclusion was that there was no significant difference between the results of the conventional tests (ex. national examinations) between the students that prepare themself using PBL and the students who use the traditional way, but the PBL students were better on clinical abilities. Another study carried by Denton et all.  reported the same results but also the preference of the students for PBL.
PBL is a student centered method, so the student has to find out by himself what must be learned, he has to process the information and activate the previous knowledge. In this way he will learn only the things that he considers to be essentials in his own style and pace. This thing motivates the student, and it is easier for him to learn, because he was the one who establish both the learning objectives and the way in which those must be archived. Another strong point of this method is that the students will gain the ability not only to identify what they have to learn but to find the relevant bibliography. So, it is very important that the facilitator not to give to the students the bibliographical resources, only to guide them in identifying the topics that must be learned. The success of the method stays in the students wish to develop themselves both professional and personal. Starting from the problem, the students will learn not only more information about the subject, but also how to learn and where to find relevant information. [1,2]
The main principles of PBL are open answer questions and study in group. The problems are the learning vehicles and the group is their fuel. The problems used in PBL session must be written in such way so the solution is not evident. To stimulate own-motivation, the problems must be realistic and the scenarios must be in resonance with the students experience. The solutions must be complex enough, they must include more interconnected parts and all the process must motivate the students to feel the need for knowledge and learning. When the students launch hypotheses in front of the group, they publicly exposed their level of knowledge and they are preparing themself for future learning. Good problems need multidisciplinary approaches and help to develop the communication abilities. . The students must identify the key concepts, to find resources and to collaborate. When a student learns and understands a topic, he automatically applies this knowledge to find the solution for the problem. He must explain it to the others, so the learning became active. Doing that, the students develop social and cognitive abilities, assume responsibilities and gain new knowledge.
The second main principle of PBL is the group study. The students examine the problem together, coordinate their efforts, cooperate for a collective scope and collaborate for summarizing and presenting the conclusions. Students will work in small groups – 4-8 persons, guided by a facilitator. To reach the maximum efficacy, the group will need 3 to 5 sessions together. Different members of the group will have, from time to time, different roles – the coordinator of the discussion, the writer, the reader of the case, etc. There are situations where the problem is presented to the group as a written scenario, which must be read, in order, but at the same time, by all the group members.
The implementation of PBL in medical education was done after a detailed analyze of the way in which doctors react in front of a patient. Barrows  divided the clinical reasoning in the following steps:
· Receiving and interpreting the information
· Generating hypotheses
· Research strategy and clinical abilities
· Formulating the problem
· Diagnose and / or therapeutically approach (conclusion)
This steps of the clinical thinking occur very fast in the mind of the practitioners so, their presence, in many times is unnoticed. PBL allows the identification of these steps and the students will gain the ability to properly approach them.  Based on this, there are many implementations of PBL method on different medical universities, the most common one being the 7 steps Maastricht method :
1. Identifying and clarifying the unknown terms from the clinical scenario – a student will write all the unexplained terms
2. Defining the problem or the problems which must be discussed – students may have different opinions about this, all the opinions must be taken in consideration, a student will write a list of the problems
3. A brainstorming session to discuss the problems, to suggest the solutions – the students are using their previous knowledge in order to identify what knowledge is missing – a student will record the discussion
4. Reviewing steps 2 and 3 – organizing the notes
5. Formulation of the learning objectives – the group reach the consensus for learning objectives, the facilitator ensures that the learning objectives are appropriate, reachable and comprehensive
6. Individual study – all the students gain information about the topics
7. The group share the information – the students solve the problem, the facilitator is able to verify if the learning objectives are reached and also can asses the students.
The role of the facilitator is critical in PBL. The facilitator is responsible for moving between the steps and for the monitoring of the group and its dynamic. This is important, because during PBL sessions, all the students must join the discussion, share opinions and discuss other ideas. 
The way in which the students are asses determines how the students learn. If the assessing is based on the capability of the students to memorize facts and information, with a big probability, the PBL implementation will fail. The evaluation must be appropriate with the PBL principles. The evaluation must be made during the group activity. The feedback of the facilitator is essential. The group must be encouraged to reflect on their performance, both as individual and as group. The evaluation at he group level (all the students receive the same grade) encourage the students to reach the PBL objectives.  Another important component of the evaluation is the receiving feedback from the others colleagues in group. This means the presence, the ability for listening and speaking, the quality of information, the ability to add value to the group etc.
Having all of this in mind, the goal of the research was to identify a proper Web 2.0 tool to be use as support for PBL. The application must cover the needs for the Maastricht 7 steps method and the research team will check its capabilities but also its acceptance from the students.