Wikipedia is hardly what I would call "reliable".
Many people claim that many Wikis are bad. I disagree, it's a lexicon
that is much better than most, if not all reputable printed lexica. If
you find a bad Wiki, please correct it, make it better.
A few Wikis are not only much better than reputable printed lexica, they
are very good, they are at least at a higher academic standard.
All non-fiction has got weak points, you'll find people writing things
like "The Lies And Fallacies Of The Encyclopedia Britanica".
Reading an article of a lexicon can't impart what 30 years of studying a
field does teach, but Wikis or something similar should be good enough
for semantics formation. I don't care about how anybody of us defines
"sysadmin" or about "levels" of administering, so I don't know this
Wiki.
Since Jerry has got doubts about Wiki articles, I wonder that Jerry does
quote Wikis too:
http://lists.debian.org/debian-user/2013/09/msg00204.html
So it might be better to disagree about the interpretation of a Wiki,
but not about the generell reliability of Wikis.