There's a new study just out from the University of Washington by Alison J. Head and Michael B. Eisenberg called How today's college students use Wikipedia for course-related research. The study covered students on six campuses across the USA. They have found that 80% of the students in the survey use Wikipedia in their initial research even if not encouraged by faculty to do so. I suspect that results would be similar at many other universities and schools in different countries. The big question of course is why they do so.
The number one attraction I think must be Wikipedia's sheer volume of information and even more important its ease of use. It is often quite simply the best place to start to get an overview of a field. Some students in the study state that they do not cite Wikipedia as a source since they know that the teacher will not approve. They all seem well aware of the potential limitations of Wikipedia but choose to use it anyway. However few claimed to use Wikipedia later on in their research where they cite more established sources.
"Overall, college students use Wikipedia. But, they do so knowing its limitation. They use Wikipedia just as most of us do — because it is a quick way to get started and it has some, but not deep, credibility."
Why this clandestine use of the world's biggest ever reference work? Using Wikipedia is an excellent way of demonstrating source criticism and you can gain a deeper insight into the complexity of many concepts by looking under the discussion tab. Why don't more teachers get involved in making Wikipedia more credible or accept it for what it is and let students use it as a springboard to more knowledge? Despite its size it is still suffering from growing pains as many committed contributors debate just how free and open the work should be in the future. Those debates are however not apparent to the average user and it seems to be the default starting point for investigating a subject area.
I found no reference to the alternative wiki-based encyclopedia Citizendium which operates somewhat in Wikipedia's shadow but has ambitions to be more accurate and peer-reviewed as I understand it. Forbidding the use of these sources just moves the issue under the radar. Using social reference works responsibly should be a topic for class discussions. Wikipedia won't just go away if we ignore it.
Read a summary of the above report in an article in Campus Technology.
Also another blog post on the use of Wikipedia by medical students on Dundee e-MedEd blog.