Matt Cutts has said in an interview (though am not quoting it here), that in his case, he wants to feel free to pass his site's PR juice to all the pages and outbound links he is linking with.
What does this mean to us? How does it affect us in dealing with the rel="nofollow" and the dofollow link attributes?
A short review: nofollow attributes will command search engines to ignore particular links within your content, it means Google and other search engines would not index these links. (although other search engines might treat nofollow differently.)
Is it really important or helpful to use nofollow? As of today, am still using it, however the bottom line about linking is "relevance". Links relevance can mean many thing to content writers and bloggers.
It tells us to link to contents that are:
3. relevant to the topic we are talking
Note: there are informative topics out there, but somehow they do not connect with the subject we are talking about - why link to them?
PS: I made this post to open ideas to you, and I hope we will have a healthy interaction in this thread. Share your ideas, correct me if I am wrong, and share your tips there
You should seldom need rel="nofollow" on links that you set up in your own web pages. Either the link is relevant and search engines should be allowed to follow it or it is not relevant and so shouldn't be added in the first place. There will be few exceptions to this where the link goes somewhere that you want people to be able to get to but where you don't want search engines following the link but in most cases you would be able to place entries in the robots.txt file so that the search engines ignore the page linked to without needing to set the link to it as nofollow.
The main use for rel="nofollow" is where you allow others to post links into your web page where you don't know whether the pages linked to are relevant or not and so want the search engines to ignore the link. Were someone to post a relevant link then you could update your page to include the link in the content you provide and then (optionally) remove it from their post.
I agree with you. rel="nofollow" also are used in most comment system, readers are allowed to include links to their comments, however search engines are told not to index them... I am still trying to familiarize the use of robots.txt, I haven't use that one yet