I have to expand on Braiam's answer by pointing out that copying and pasting in stuff from other websites (even in the tag wikis) is unacceptable. Our [Terms of Service][1] stipulate in section 3:

>You agree that all Subscriber Content that You contribute to the Network is perpetually and irrevocably licensed to Stack Exchange under the Creative Commons Attribution Share Alike license.

By posting, you grant a license to content. If you don't own that content or can't justify its use as fair use, you've fraudulently given Stack Exchange a license for something you had no right to in the first place. It's wilfully illegal and puts Stack Exchange in a bad position (that's why these clauses exist in the first place).

We can't allow behaviour like that.

  [1]: http://stackexchange.com/legal