Instead of doing url redirect, I am thinking of moving my content from my old site to a new site by deleting the urls from old site. Do you thing its okay? Google won't penalize my new site considering it as duplicate content as it may have cached content from old url on its database? Or, do you think I should simply redirect all the old urls doing 301 redirect to a new site? Since my old site has only 15 pages and may be like 400 backlinks, what do you think I should do? The old site has page rank 3, but due its poor extension it has been doing terrible on search engine ranking. This is why I want to move the old site's content to a new domain. I hope I made myself clear! Any advice would be greatly appreciated. I am really confused!
First off, Throwing away built back links and deleting URL's from your old site is not a good idea, since your previous built back links would be just put to waste. I strongly suggests that you use the 301 redirect if your new site would be set in a different url, having a fresh url from the web means low or most of the time gives NO traffic. Having your old site as a redirect referral to your new site won't hurt. BUT, if you're going to just replace the pages or contents of your old url's with new content or new pages, you dont have to worry for being penalized by google since when they re-crawl your old site URL with newly replace contents, your site cache would also be over written, creating no duplicate contents.