No follow links can be used in internal links. If you want some pages not to be indexed by search engines you can make that link as no follow link. For example: Open Facebook's home page, you can see a link "Forgot your password?". That link is a nofollow link.
No that's not true. If you don't want it to be indexed use the meta tags! For example: <meta name="robots" content="noindex" /> Or use the robots.txt alternative! But rel="nofollow" is absolutely not the way you should do it, because it influences your site's ranking in a bad way!
Who told you so, you must not use nofollow for internal links ever. you can use it for external links on your site, or on the comments that you receive on your content.
Its better if you don't use nofollow for you internal pages because that will restrict the flow of any link juice to the inner pages and you won't get the benifit of the main page's PR but also won't be able to get the benefit of the homepage to rank any inner pages.
Suppose you need to insert a cookie to block your own traffic from being recorded in your google analytics account. Then that page shouldn't be indexed by google for which you need to use the nofollow attribute.
No, nofollow lnternal linking does not bad impact on your site Page Rank. its depend upon where u put nofollow internal linking like if you put nofollow link on any keyword then its not ok and if you put nofollow internal linking any word like some sites you will see like Read more, continue reading with hyper internal link there we can use nofollow link.
Don't need to do that. If you want web page not to be indexed by SE then you can make link no-follow...
I don't think so you need to do use no-follow tag on an internal link for you own website.Don't use it. Do-follow link helps to flow of PR juice to all your web pages...