Hi, I have started a brand and purchased .com and .net domain associated with my brand name. Since both those domains points to the same site, does that affect my ranking in google. I have seen in google guidline that multiple sub domain, domain etc with duplicate content will be penalized. Since I need to protect my brand name I had to do that. Is that a problem? Please help me.
I believe you mean that you have your main site at .com and then .net and other redirects to .com and if this is the case then I don't see any probs in it. Many sites do this and even Google uses a number of typo domains to redirect em to the main one.
There is no problem with both the .net and .com domains as long as both have unique contents. If both are same and one site redirects the visitor to the other site, then go to google webmaster tool to learn more about this topic which I think will help you clear your problem.