Many Webmasters, Bloggers (I think one and the same) hates “No Follow” term. and yes its obvious. Commenting on others blog, etc things can give you backlinks if they are “Do Follow”, but now a days most of the bloggers are using No Follow tag in there comment section (and even me too, My Blogs comments were do Follow, but now they are No Follow).
Google Blog , Officially stated that “We encourage webmasters to use No Follow tag in there comment section to avoid Comment spamming”. you can read more here.So Google bot will never count No Follow tagged links in terms of Pagerank Juice.
Yet another reason to use No Follow is “Bad Neighborhood“.
If we give Do Follow link to any Bad site such as Casin0,P0rn etc, will harm your Pagerank and overall quality of site in terms of Google. and if our commentator will use such link then this may be harmfull for our site ranking only ..
So i populate few reasons or you can say few things,
“Where to use NO FOLLOW and where to use DO FOLLOW ?” in our blog.
These conditions are also applicable in your normal posts.
Where to use Do Follow
1. Related content sites.
2. Blogs who shares Pagerank Juice with others
3. High quality blogs (In view of Google e.g. Official Google blogs, etc)
4. Your Friends 
5. From where your copied the post (If you copy something)
Where to use No Follow
1. Unrelated content sites. (Not related to your post topic)
2. Sites who never share there Pagerank Juice with other (Like Wikipedia, Youtube)
3. Your Feedburner Feeds (Why your Feeds need high Pagerank ?)
4. Casin0, P0rn etc like sites.
5. Affiliate Links (Why give them double profit ?)
6. Bad Neighborhood (Its you, who decide who is bad and Whos Good)
I will frequently update this post, if i got more reasons .
Look at this Image,
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Jul 22, 2008 at 3:47 pm
Great guide Bro !!
I hope i am not a part of bad neighbourhood !!
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Jul 22, 2008 at 3:49 pm
@Abhishek
You comes under My Friends section
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Jul 23, 2008 at 1:02 am
Chetan, I was looking for NoFollow and DoFollow differences but most of the explanations is too lengthy and at the end I still don’t get it..
This particular post clears my question on DoFollow and NoFollow… I don’t really agree with the reason of sites like p0rn, casin0 getting backlinks, because, if such comments coming from this sites, we would have moderate it anyway..
How you DoFollow and NoFollow on certain comments at one time? Can it be done?
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Jul 23, 2008 at 1:13 am
@Atniz
)
Hi,
About P0rn and Casin0 links, actually Google or even normal people counts these sites as BAD, so we should avoid them, and what if we have 100s of comments on a single day !! (Its my dream
Then its bit difficult.
and about DoFollow and NoFollow in certain comments at once according to Admin choice, i am searching for such plugin which can allow us to do, but as WordPress is totally php based,(forms at run time) its bit difficult task for programmers .but as soon i get anything like this, i will post it in my blog..
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Jan 2, 2009 at 8:21 pm
If Google considers Casin0 and P0rn websites as bad then their PR would be nothing more than 0. Just don’t link to websites you think are shady, and if you have to then just you the nofollow tag.. simple!
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