nofollow and dofollow lins

nofollow means although you have placed the link, you do not necessarily recommend it. dofollow means you do recommend it. 

This makes dofollow more important. 

Google doesnt get happy when it sees a lot of irrelavent dofollow links going out of your site. So make sure  your links are relavent to your LOB (line of blogging)

I've make my blog dofollow.. I've replace nofollow to dofollow.. but while commenting, it does not ask for any URL or something for backlinks... the coment box is as it is.. I'm bit confused..

what is the difference between the two comment boxes? 

1) the simple comment box (Using capta)

2) and other is Using E-mail, URL..

I'have capta type comment box now.. how other blogger can get backling from my blog without an URL?

Are you saying that you have made the comments in your blogs dofollow? Or is it something else?

And regarding the comment boxes, I think that you are somewhat confused. You are using the default blogger commenting system. And the two types of comment boxes you have mentioned above are the same. You can enable or disable the captcha. And, you can enable or disable the Name/URL comments with which people will be able to post comments on your blog without logging into their google or other accounts.

 how other blogger can get backling from my blog without an URL

When you make comments on your blog do follow, any links placed within the comment as well as the link to the profile page ( or the URL in case the blogger comments using Name / URL ) are do follow.

Consider that you liked some website very much ( say Indiblogger.in )  What would you do next? Probably, write a post on your blog about Indiblogger and you would also link to IndiBlogger. So, a link to a certain extent implies that you like that site and it is probable that other internet users also like it. So, google displays sites with more links in the first few pages of search results. ( Other factors also also used to determine to the ranking of web pages in search results )

Now , say that you have written something about a site which isn't very useful and do not recommend it to your blog readers but still, you might write a blog post about it to share your view on how websites shouldn't be designed or something like that. Here too, you will provide a link to that site.

So, how do search engines know whether you are recommending a site or not. The answer lies in 'do follow' and 'no follow'.  Do follow means that you are recommending a site. No follow indicates a neutral opinion. ( No follow doesn't mean that you are not recommending the site )

By default, links you post in your blog are do follow. The HTML looks something like

<a href="www.example.com">Example Site Name</a>

If you want to make them no follow, modify the HTMl to:

<a href="www.example.com" rel="nofollow">Example Site Name</a>

In blogger, you can mark a link as 'nofollow' by selecting teh check box 'Make link nofollow' while inserting the link.

Note that there exists nothing like rel="dofollow". Links are automatically do follow.

By default, links placed in comments on blogger blogs are nofollow. 

And finally, coming to the importance of do follow links: They help you to rank higher in Google search results. The more the number of do follow links, the higher the ranking. But ranking also depends on the quality of links. There exists a metric called page rank. Do follow links from pages with higher PageRank have more weight than do follow links from pages with lower page rank. And page rank itself is calculated based on the number of links and the page rank of the pages which link to the current page. So, it is a kind of cycle. Obviously, there needs to be some starting point. But, that is important for the Google engineers but not for us. What is important for blogger who are targetting search traffic is higher number of do follow links from pages with higher page rank. In simpler words, more links from good websites. 

And since your blog is about photoshop which people google for, links are definitely important to you.

Wow.. tahnk u very much Ranjith..

now I understand these links.. I've made all links to nofollow earliar.. bu I'll change for better ranking.. 

Hey you have to make external links from your Blog as no-follow to stop leaking SEO juice from your site.

Read Here about How to Make External Links as no-follow

Vallabh it all depends what that link is all about. In simple terms if you put a do follow link you advise google to follow it, if you put a no follow link you advise google not to follow it. If someone is putting a guest post on your blog they obviously want the link to be do follow so that link juice can be passed. 

Blog: Sunset Talks-Guide to Goodlife

Please do not post links to your blog in forums. 

Thanks 

do-follow used to count as a popularity vote..!!

I dont get this..  suppose I have to use one hyperlink in my post.. then which link is benificial? 

Do-follow is most imporant for google while no-follow is less (debated) important. A do-follow used to count as a popularity vote.