> I'm going to say: anyone can look [Wikipedia articles] up.
Not only that, but the Wikipedia format is far more conducive to making artifacts. If you quote a Wikipedia page in a mailing list, then whatever it said on that day is forever in your archives. If the source page ever gets updated, corrected, enhanced, you lose. Er, we lose.
Sending a link is fine; explaining your reaction to something specific in a (for instance) 36 "page" article is even better.