It's worth mentioning that Panda, a google algorithm update, deals with this specifically. Sites with large swathes of duplicate content or pages with very little content are penalised quite heavily - the idea is to prevent people who's sole purpose is the ranking of keywords. Each page either has to have a good portion of good, unique content or you need ensure that it is kept out of Google's index, by using meta robots tag (noindex, follow) or by preventing crawling using robots.txt

It's worth mentioning that Panda, a Google algorithm update, deals with this specifically. Sites with large swathes of duplicate content or pages with very little content are penalized quite heavily - the idea is to prevent people who's sole purpose is the ranking of keywords. Each page either has to have a good portion of good, unique content or you need ensure that it is kept out of Google's index, by using meta robots tag (noindex, follow) or by preventing crawling using robots.txt