I make extensive use of Jim Wale’s Wikipedia, ( http://www.wikipedia.org/ ) but I do have some reservations.
I find their technical articles ( math, science, technology, engineering, etc. ) rather good. The articles must be limited and superficial since Wikipedia is not a book or treatise publishing activity. However, these articles generally have extensive bibliographies into the periodic literature as well as published treatises and ArchivX material. Follow the pointers and one will soon be awash in information. Wikipedia is a rather good way to get to the heart of the corpus of data on various technical matters.
In the area of political issues, Wiki has unfortunately been co-opted by competing interests of broadcast their views. One must regard such articles con grano salis. It is to Wikipedia’s credit that they have modes of correction and objection to material that is either not supported or is skewed or just plain wrong. Considering that it is an open medium, they do o.k. One just has to be careful.
So I give Wikipedia my mixed blessing. For the kinds of things I use it for (Math, Physics and such like) it is rather good.
In a related manner I also give http://plato.stanford.edu/entries/ my qualified blessings. Once again, it is a good way to drill down into useful material, particularly in the realm of philosophy.
They are brilliant examples of how our semi-capitalist system provides very valuable services to the general user for little or no cost. The above mentioned services are free (they do not charge). However I contribute moderately to them, because I have gotten rather good value. Anything like that should be supported voluntarily within one’s means.
Bob Kolker