Here is a nice article on how to deal with duplicate content.

http://googlewebmastercentral.blogspot.c...ntent.html

It offers some guidelines which can be followed by the webmasters to save themselves from duplicate content problems.

Use of Robots.txt, Nofollow links and other simple things can really improve the over performance of the website.

i wonder if i get penalised for the lo fi version of my invision power board forum. its a duplicate of the site that uses a more "spider friendly" skin.