If you want your site to rank high in search engines one of the things you need to do is to build backlinks to your website. We often hear in the context of link building about do follow and no follow backlinks. Prior to going further we must understand what  do follow and no follow  tag means because they have a big influence over your search engine placements.

The do-follow or no-follow tag is chosen by the website owner or the blogger. You can see below the regular syntax for an HTML link:

<a href=”Your URL”>your anchor text</a>

So what are the components included in this HTML structure?

1. HTML tag for reference  - <a href=
2. URL to your page -Your URL

3. Your anchor text -
4. Closing tag – </a>
When you do this you  basically ask web spiders to crawl the link from your page by default.
The additional tag will help you control whether the web spider will crawl deeper from your site following a link or not but by default it is a do-follow. So it doesn’t matter if you are not adding a do-follow tag, it automatically crawls through it.
If you don’t want spiders to crawl the link from your site, you have to use a no-follow tag in it as it follows:
<a href=”your URL” rel=”nofollow”>Your anchor text</a>

How do the dofollow and nofollow tags affect your search engine placements?

Nofollow tags -When you leave your site’s link to others’ websites, you need to check if their site allows you to get listed or not by using a no-follow tag. If they have a no-follow, it is still a good idea to put link to your site there, but not useful if you are trying to boost in your search engine ranking with it.
These days many sites and blogs uses no-follow tag in them in order to attract discussion in their base. So it is a waste of time to put your link on them with a desire to boost your search engine ranking. In the same time this is a good opportunity to build your  exposure in the community, to put instance to click.
There are a  few reasons why people don’t want to give their link juice and use the nofollow tag:

-There are many people that offers  links against payment and choose to associate it with a no-follow tag because Google wants it this way.

-If you allow spiders to crawl through a link helps in passing a small amount of rank juice to the linked site, if you have too many links pointing out you can be seen as a farm link by Google and you get penalized.

-It is very common to use no-follow tag while linking to major sites like Google.com, Yahoo.com because their popularity is so big and by giving do-follow or no-follow does not make any difference to them.\
Dofollow tags –  The dofollow backlinks are Google’s favourites if you are looking to increase your website’s rankings. When your website receives a backlink from a high PR page and the link has a dofollow attribute, part of that PR is passed along to you.
Ofcourse the search engines’ algorithms are very complex and a dofollow backlink from a high pr webdesign website sent to an iphone site might not be as effective such as a low pr backlink coming from a phone review site.

Conclusion:

Both do-follow and no follow backlinks can increase your ranking and traffic. The do-follow backlinks are efficient for bringing direct traffic or for increasing your search engine rankings indirectly( other people see the nofollow backlink and decide to link themselves to your website).
The Dofollow backlinks can definitely increase your rankings, if you aim to rank high in the search engines you should look for ways to increase especially the number of dofollow backlinks to your website.