Loren Baker post about the “No Follow” attribute is very much interesting.

1. How does your search engine treat the No Follow attribute?

• Google : The Googlebot does not follow that link.
• Yahoo : If we find a link we make it available to our algorithms to find new content, whether it has a ‘no follow’ attribute or not. However, if the ‘no follow’ attribute is present, it means that no attribution is given to the target from the source of the link.
• Ask.com : We have never officially supported No Follow, so your questions don’t apply to our crawler/ranking.

2. If a site has no web citations and only has one link pointing to it, and that link is from a Wikipedia entry, would your search engine find that site and index it even though the link uses a No Follow attribute?

• Yahoo : Yes, the link is available to our crawlers for finding the target. Then the target will be crawled and indexed based on our algorithms.
• Google : Assuming that link is still no-followed per Wikipedia’s current practice, we will not find much less index that page (remember, this is page, not site related; if links to other pages on that site are not no-followed, we will see and potentially index those pages).On a related note, though, and echoing Matt’s earlier sentiments… we hope and expect that more and more sites — including Wikipedia — will adopt a less-absolute approach to no-follow… expiring no-follows, not applying no-follows to trusted contributors, and so on.

3. Is there any quality given to sites which attract No Follow links from authority sites, besides the lack of the passing of PageRank, Link Authority or “Search Juice”?

• Google : Since the Googlebot does not follow no-follow links, this isn’t really an issue.
• Yahoo : As promised in the semantics for the ‘no follow’ tag, the anchor text and attribution will not be carried over to the target of a ‘no follow’ link.

In other words, “no follow” attribute is not really that effective.

In conclusion, the commenter was correct about links to pages from Wikipedia some search engines, specifically Google, but Yahoo and Ask.com both not only follow No Follow, but also make those sites available to their algorithm. Therefore, even links with the No Follow attribute do have value; especially in the counting, but not always authoritative measurement, of backlinks.

This is the reason, I think, why spammers are still comment-spamming some exploitable and unprotected blogs.

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