NoFollow Tag can be used on any site or Blog. If someone else is placing a link to your site or if you are linking to something shifty as an example of something shifty then that would be a good time to use the NoFollow tag.

What the NoFollow tag looks like or How to Use NoFollow Tag in Webpage or BlogFor SEO:

Many bloggers have amazing link popularity due in part to comments they left on other blogs or web 2.0 applications. This will cause lots of blogs which were primarily connected by comments to lose a good bit of their link popularity.

Many automated blog spam scripts may work harder to find the blogs which are slow to change. While the number of spamable blogs will go down the value of effective blog spamming will go up. Bloggers will have a big riot celebrating this move. After time passes they will still get spammed and realize that this will not immediately cure the problem.

More bloggers will get approached with a bit of $$$ for writing editorials. More bloggers will sell out.

Some people who were posting useful and thoughtful comments in part to gain link popularity may post less often.

Some worry that people will abuse this NoFollow tag for SEO purposes, but those who would do that could just as easily use other redirects, so I really do not see any change there.

This change does make the role of link popularity (and how to keep it) much more visible. The keep your link popularity line of thinking may kill off a ton of natural linking, which in the end really does not help anyone. SEOs might rush off to make their own blogs. Certainly the editorial side can be handled on the cheap

Blog comments sure did make it easy to rank good about a year ago...