Wikipedia's become fairly ubiquitous, but I'm wondering if it's appropriate for the Wiki here --- here's what I'm trying to say: A moderator just added a few tags which I find very helpful. So I wanted to return the favor and give a Tag wiki description because it is obscure and I happen to feel comfortable in explaining it. Once I started to create the wiki, I realized that the wikipedia entry says it far better and more thoroughly than I ever could. So is it lame or just bad practice to merely have a link to it in the description? (My rep's too low to create a tag wiki without it being approved first anyway, but I want to save someone the trouble of out right rejecting because this might be incorrect procedure.) thanks
While you can quote Wikipedia in tag wikis (but not excerpts) as long as you attribute it correctly, it's generally discouraged.
If you're asking about making the tag wiki be little more than just a link to Wikipedia, then don't do that. They should be useful and informative by themselves.