Wikipedia copyright

All contributions to Wikipedia must be licensed by the author under the GNU Free Documentation License (GFDL). While it guarantees a number of freedoms to reuse and modify the work, this license also imposes obligations that can make this reuse burdensome. Authors always remain free to copy their own work, but cannot copy work that has been edited by others unless they comply fully with the requirements of the 3,289-word GFDL.

The requirements of the Wikipedia license include:

• any derivative work must be licensed under the same conditions
• there must be attribution of principal authors
• the lengthy text of the GFDL must usually be included
• 15 conditions with respect to distributing modified copies

As with Conservapedia's terms, no special exceptions are made for teaching or other non-profit uses, but in both cases the fair use provisions of copyright law apply.

Conservapedia's copyright conditions are generally less restrictive and easier-to-use, but may be revoked "in very rare instances of self-defense" and do not allow for entire sections of the site to be copied or mirrored, unlike the GFDL. For details, see Conservapedia:Copyright.