Last week, I had a basic test about SEO. And I found out that there are some words which are useful in SEO while confused me. I am not sure if you also have the same problem as me, but hereby i would like to make them more clear.
1. Nofollow and Dofollow
“Nofollow” page is very popular in SEO. Actually, “Nofollow” is a HTML page code. You can not see which page is “dofollow”or “nofollow” directly from the webpage until you view the page source.
Firstly let’s take a look at this, this is an example of Dofollow link:
<a href="http://www.linkbuilding.com"> Social Media Specialist's Blog</a>
And Nofollow link is like this:
<a href="http://www.linkbuilding.com" rel="nofollow">Social Media Specialist's Blog</a>
With the nofollow code, generally speaking ,a webpage cannot be shown in the index through search engine algorithm. In other words, if we want to stop some text link advertisements(which is shown on our blog or own page)to not be read by search engine, we can always put the nofollow code in. For further explanation, please read here.
2. Robots.txt and NoFollow.
Robots.txt is a text file, the format is like this:
# robots.txt for http://www.example.com/ User-agent: * Disallow: /cyberworld/map/ # This is an infinite virtual URL space Disallow: /tmp/ # these will soon disappear Disallow: /foo.html
It is a text file you can edit and put in your website while Nofollow is a meta tag. Robots.txt tell the search engine what in this page should be read or not.
Generally speaking ,the biggest difference between Robots.txt and Nofollow is that:
With Robots.txt, the search engine cannot crawl the page.
With Nofollow meta tag, the page is still crawlable, but in search engine’s index, this page is not shown, and there will be no out going links from that page, no pagerank flows either.
(Further details please read here)