Would anyone give me an example of no-follow and do follow so that i can understand the difference between both these attributes?
Say you have a blog that allows comments. And people post comments including a link to their site. Very common. And it used to be done (and still is to some extent) to create backlinks. but it's a bit spammy. So you can set up your blog so that all of the links in those comments are "no-follow". Your basically telling Google (and other engines), that while you've allowed the link on your site, you're not really vouching for it and would prefer if they don't pass along what is called "link juice" from your site to that site. Link juice, in a nutshell, is a vote you are making in favor of a site by allowing a link to it on your site. So a no-follow links says you don't want to "vote" for it. Do-follow links are obviously just the opposite.
The links which have 'No Follow' attribute are called No follow backlinks and others are Do follow backlinks. Do follow backlinks add some value to your site authority.
Do follow is hyperlink inclusion that tells search engines to pass on any credibility or influence to an outbound link. When Google bot visits a website it reads website pages and includes links with do follow attribute and excludes link with no follow attribute. Nofollow is html tag that website owners, add to links in their website for the search engines not to crawl, notice, or acknowledge a link. While a nofollow link is ignored, but popular social networking site like Twitter, Facebook, LinkedIn, Myspace sites are nofollow, but they do provide a lot of other benefits.
There is a major different between Do follow or No follow link. Do follow links are follow by the search engine and No follow links are ignored by the search engine for the crawling.Do follow links are so beneficial for increasing website page rank. you can check the links which are do follow or not just check it the following attribute in the source code if link have following attribute like rel="dofollow" then the link is Do Follow link or if the link have following attribute rel="Nofollow" then that link is No Follow link. you can find this attribute in anchor text which are used in the page source.