Guest comments work to a certain extent. If the guest posting is not content rich then it will be of no use. No way the comments posted by other guest would have required keywords, it needs perfect keyword density to be enlisted anyway or to be of any help in increasing page rank or traffic.

I don’t think that you understand what I am saying here.

I meant those blogs that got a lot of traffic. If you are going to produce an article for them then they are going to give you a back link to their site.

I disagree as guests to post on the forum / site as they can write what they want to use bad words, or are those who have nothing to do with the information they provide on forum, they are guests have no interest to help the forum/site

Machida, if your using links back to your site in all your comments that may be why they're not being accepted. Try posting useful comments with no links, over time, people will check your profile and visit your site. Work's much better over the long term and you will get a steady user base.

Yeah, that's a good thing to remember, try to make yourself known on that forum, posting on forums with useful information that might help others!

I’m not talking about commenting on blogs. I am talking about creating a blog article and then you are going to submit it to blog owner. If they are going to post it on their site then you will get your site mentioned and a free back link on that certain blog post.

Maybe it's like posting on article directory or any other free to republish article sites.

But, I never know about people that want to write for another blog for free

You got it right. It is exactly like creating article for article directories.

Other bloggers would want to write for you for free if you have an establish blog. Writing for you in exchange of back link to their site will give them an edge over other bloggers since they would get a free traffic and back link in the process.

I think it really would depend on what you mean by "Guest Posting"

but most Blogs require you to be added to the author list by the Admin to make a regular post, and even to leave comments you sometimes need to wait for an Admin to approve that as well.

Guest posting only mean one thing and that is to create an article and post it on an establish blog.

You don't need an author account since all you have to do is to submit the article to the blog owner and then they will decide if they would post it or not.

Maybe on some Blogs, they let you just submit articles for approval...but there are plenty of others that require you to register an account and get it approved by the Blog's Admin before you can write any articles there.

No doubt, if you make guest post in a popular blog then you will get good exposure.
I want to make guest posting too, but too bad as far no one accept my article due to grammatical error. Any solution?