stewartcs said:
Not entirely no. However, in my opinion it is definitely better than a source that can be "reviewed" by self proclaimed experts with no credentials.
CS
But the system still works. Wikipedia really took off after 2004 or 2005. From that period onward the science articles improved in quality, because from then on there were a huge number of Ph.Ds, postdocs etc. who started to contribute. They keep science articles of their interest in their watchlist and revert any changes that are not appropriate.
The experts have organized themselves on many special wiki projects, like wikiproject physics, wiki project mathematics etc. etc. Problems are discussed there.
Wikipedia does not have original articles that you could publish in peer reviewd journals. It is an encyclopedia about well established facts. So, one should compare the performence of wikipedia with other resources (online or books). From my own experience I can say that wikipedia outperforms any other comparable source because of the constant monitoring by experts.
Some time ago I emailed MathWorld about an error on their page. It took them a year to respond and correct the error. Any source like MathWorld edited by a handful number of editors would face this problem. A paper source is even worse, you would have to wait for the next edition.
B.t.w., Eric Weisstein's world of physics, which is supposed to be edited by vetted experts, simply cloned many wiki articles. In case of some thermodynamics articles, that was a fatal mistake, they cloned some erroneous versions, http://scienceworld.wolfram.com/physics/CombinedLawofThermodynamics.html"
