Wikipedia copyright

All contributions to Wikipedia must be licensed by the author under the GNU Free Documentation License (GFDL). While called "free", this license actually imposes burdensome obligations that interfere with the reuse of this material, even for teaching purposes. Authors always remain free to copy their own work, but cannot copy work that has been edited by others unless there is full compliance with the requirements of the GFDL.

Here are a few of the complex requirements of the Wikipedia license:

• any derivative work must be licensed under the same conditions
• there are 15 different conditions with respect to distributing modified copies
• there must be attribution of principal authors
• there is no exception for teaching or other non-profit uses
• there must be inclusion of a copy of the lengthy GFDL in many cases

For Conservapedia's less restrictive and easier-to-use copyright, see Conservapedia:Copyright.