Yes, they are - I strongly disagree with anyone who says otherwise. A site with strong off page SEO will have backlinks from many quality sources, so it stands to reason that a percentage of them will be no follow. The search engines like natural looking and varied links. Why wouldn't they?

True. It seems to be helping my ranking, so I'll continue what I'm doing.

The key in winning the backlink competition is "variation" you don't want your links just coming from one source. You want them varied as much as possible (no follow links included).

some says no follow link also counts

I think so. Although it is hard to tell, since we do not know what backlinking Google finds normal

Alexa is just a traffic ranking. You could climb or fall with or without any types of links.

Yes, Alexa ranking is based on traffic. When visitors using the Alexa toolbar land on your site, your ranking (theoretically) improves. It makes sense that your Alexa ranking improved because visitors may have clicked through your comment link.

Now to the debated question... Do no-follow links count in terms of ranking? Honestly, you can hire someone to build comment links on other blogs for about .50 an hour so why not build a few hundred a month? In any case, whenever I have a question about ranking, I think: What would Google think? Would Google want to improve the ranking of sites that receive links from comments and no-follow tags?

Ultimately I believe that the comment strategy is so easy to cheat that giving anything but a tiny amount of credibility to a no-follow link would be foolish. On the other hand I think it would be unfair to discount them altogether. Personally, I wouldn't participate in commenting for the sake of link building, but as a natural part of communicating with a target industry, commenting is a great idea.

Commenting not only builds no-follow links, but it attracts targeted visitors (if your comments are good) and the attention of related website owners (who can possibly become partners.)

Thanks,

George

Yeah the certainly DO help! As already mentioned a good "portfolio" of backlinks will include links from both high PR and low PR, do follow and no follow.

do fallow links improve your ranking fast in search engine

According to Google they do not count.

"If you're a blogger (or a blog reader), you're painfully familiar with people who try to raise their own websites' search engine rankings by submitting linked blog comments like "Visit my discount pharmaceuticals site." This is called comment spam, we don't like it either, and we've been testing a new tag that blocks it. From now on, when Google sees the attribute (rel="nofollow") on hyperlinks, those links won't get any credit when we rank websites in our search results. This isn't a negative vote for the site where the comment was posted; it's just a way to make sure that spammers get no benefit from abusing public areas like blog comments, trackbacks, and referrer lists."

Official Google Blog: Preventing comment spam

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Yeah, My friend, Alexa ranking is depend on traffic and it's only count when Alexa tool downloaded in browse. search engine ranking is depend on who many link you count as backlink. if you used no follow links then you can get Alexa ranking but can not get position in search engine ranking.

Nobody knows accurately because more than 200 factors have impact on keywords ranking. However, there is no doubt that it can increase the diversity of your website's links and more traffic to your site. The relevance may be that more traffic to your site can also impact on keywords ranking.

Yes, I am sure. My site got improvement by no follow links. But the site page rank is higher.

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Yes it is beneficial because it will add to your collection of links