what actually is do follow and no follow forums

A do follow link on any site, be it a forum, blog or other means that:
1. the link will get followed by the search engines (meaning they will have a look where it goes).
2. a certain amount of value has been passed from the site linking to yours. All these link values are added up to help contribute to you getting found within the organic listings and getting page rank.

A no-follow link means:
The link will be followed but no value will be passed from the site linking to you.

Hope this helps

A no follow link contains html code that tells search engines not to follow the link.

A do follow link does not contain any code that indicates the link should not be followed.

HTH

Another explaination:

There is an extra bit of code you can ad to a link to tell the search engines not to follow it. It looks like this:

<a href="http://something.com" rel="nofollow">

The rel="nofollow" tells the search engines to ignore that link. Because of all the abuse of signatures on forums, many forum owners have had to add that to all outgoing links.

It's an unfortunate thing to have to do. The reason why it's necessary is because forum owners want to have high quality posts, not a bunch of people posting junk just to get their signature link in there.

Please don't go around spamming forums with useless comments just to get your signature in there. From a marketing perspective, there are many better things you could spend your time on. You're just annoying forum owners and forcing them to put in extra meausres to discourage this sort of thing.

There are some marketing benefits to participating in forums, such as building networking relationships and personal repuation. Backlinks from signatures are negligable, especially if you're, say, posting a link about a HD media player in a webmaster forum

Some CMS (including wordpress) also use rel="external nofollow" attribute value, though this convention doesn't show up in references.

That said, forums will send you a LOT of traffic, if you participate in discussions and build a reputation with your thoughtful post, the signature links are just bonus.

There has been a LOT of confusion about whether SEs crawl the nofollow links, I would say; yes they crawl the nofollow links as we know them now. Earlier nofollow and noindex attributes were limited to meta robots tags and meant that they shouldn't be followed or indexed.

@Megan
yeah you are absolutely right and i just want to attract some visitors to my blog with the link i posted in the signature ,so i need some info to drive the visitor to my blog and thats the only reason to post the mediaplayer deal in the forum signature ,anyhow thanks for letting me know some useful stuff
you said "building relationship and personal reputation",would you mind elaborating it, why am i asking because how come one build the relationships in the forums and what to do with reputation if i get?i would be very grateful if you let me know about these so that it may be helpful for my blog in anysense.

When creating a link on a webpage using HTML, the standard code for that link is:

Search Engine Optimization

It includes the HTML tag, the URL the link will be going to, the text that will be shown on the webpage for that link, and the closing HTML tag.

You are able to add more HTML to the code above, in order to tell the search engine spiders whether or not you want them to follow the link when crawling your website. You may be thinking… “Why wouldn’t I want the search engine spiders to see all of the links on my site?” This is a very valid concern, which I will address further down. First, I am going to show you how to modify the HTML in order to tell the search engine spiders to crawl a link or not.

To tell the spiders to crawl a link, you don’t have to do anything. Simply using the format shown above, the search engine spiders will crawl the link provided.

To tell the spiders to NOT crawl a link, you need to add the following code to the HTML code above:

rel="nofollow"

It would then look like:

Search Engine Optimization

Basically, there is no true “dofollow”, it is just NOT using the “nofollow” tag. Pretty simple, eh? (No, I am not Canadian… well, kind of.)

Why does this matter?
When you are using different methods (hopefully from this site) in order to build links on other websites (to increase your search engine rankings), you need to determine if the websites you are attempting to get your site listed on use the “nofollow” tag or not. If they do, it may still be a good idea to try to get that link there, but it is generally regarded as not the best use of time since the search engines don’t follow that link and you don’t get any increase in search engine rankings from that link.

this was the information i collected when searching for dofollow and nofollow,may be this might be useful to anyone who logged into marketing recently ,thought this information is copied from here
http://www.inlineseo.com/blog/2008/03/15/what-is-dofollow-what-is-nofoll...

Can a forum change from being dofollow to nofollow? What if you are posting there and the moderator decides to make a change, I'm assuming that's possible, right?

re=nofollow contains in a anchor tag means the link will not crawled by google and will not get any benefit from it on Google. If any anchor is without rel=nofollow means its dofollow and google will index the link and chance of getting BL if Google found the link

But if you are looking for traffics as with backlinks then you should join do follow forums.

Dofollow forums will use dofollow tags for your signature and other links and Search engines will give you good response for this types of links.

Thanks

Thanks Megan, yeah I thought that moderators could change do follow to no follow links. That's an interesting point that followed links are a privilege, not a right. But yeah, maybe they are not such a privilege, if Google doesn't really give it much weight anymore (assuming their algorithm's improved to detect and rule out forum signatures).

There are many reasons you would want to use the “nofollow” tag,

such as:

* Maybe in your blog’s comment section (if using most blog software, this is automatic). It is up to you if you want your commentators to get link juice back to their site. It is personal preference.

* When linking to major, very popular sites. If you are linking to google.com, yahoo.com, digg.com (the front page), cnn.com, or whoever else, they are already popular, so you might as well use “nofollow” since your link won’t make or break them.

if a blog allows a dofollow tag what is the disadvantage or if it follow nofollow tag what is the advantage

i mean what a blog will get putting a dofollow tag ,is that will it bring any negative publicity to that particular site

what i understand is if a blog allows a dofollow tag and if google spiders follow that link,if they found that link is spam or not a good website,the site which has given the dofollow link will be affected in page rank ,am i right?

You have to control your own site when you allow do follow links like deleting spam comments. Like Megan said, it will penalized you in SERPs ranking.

I agree with all of you here!

This is the closest to my need. I heard the dangers of dofollow, you know I am just a noob in SEO world. So I have a very serious question:

When I write an article referencing some good links which I believe are good to my readers, should I put that nofollow?

Thanks

As far as I know,paid links also are marked as nofollow. so i don't know what will happen in the future.

Dofollow pass on PR, which is why link buying is such a big business right now. Nofollow on the other hand doesn't pass on PR. While some link builders opt for nofollow links, this is the preferred way as Google sees it for paid links.

Posting on no follow page is nothing but wasting time. For paid link which is no follow..... absolutely no!

not hard to reach the top of Google . You shouldn't have to pay a dime to rank high if you know what you are doing. I sell vettes online and own the top spot. Google me. (RICK DANIEL) (CORVETTE KING) 34 million strong. ..backlinks help of course but you have to blast your name to the top or you aren't seen