I am not sure what to do. Say I have a site: www.mysite.com. For SEO: Will it make sense to create a blog at blog.mysite.com (how much impact does the traffic have on rankings?) or Will it make sense to create a new blog website www.myblog.com and set links to your own website (www.mysite.com) from the blog. Ok, one more thing. If I do both with similar content, will it become a duplicate content problem? I am too confused on this. Please help.