There is no rule of thumb for this... Secondly, you can't just post on one site, you need to find dozens of more article directories, hundreds of high PR blogs for posting comments... and much, much more!
Getting tons of links from one article directory pointing to the same web page won't do anything for your page's PR (it no better than just having 1 link)
Is this saying that you should only write one ezine per website???? I thought they were a high authority article site and so better than some others.
Writing articles is for the purpose of getting traffic to your website, since it is a lot easier to rank an article high in search engines(and even if you don't, you'll still have some traffic), than it is to rank a new website. Writing EZA articles for the sake of backlinks is pointless.
For me well, dont depends only on submitting articles in a higher rank. Build link also in forums, high PR blogs in same niche and press releases.
It all depends on what the Pagerank of your articles on Ezinearticles.com is. For example, of my 200 or so articles, about 80% have pageranks from 1-4. My past experiences lead me to believe that one of the pr4 links to one site will make that site a pr3. This is just my experience, rebuke if you want. It's also been my experience that Ezinearticles is great for targeted traffic, if the reader likes what you've written and you've embedded the links properly in the 'bio' you are almost guaranteeing them to visit the link. I agree that you shouldn't just use Ezine for all your articles or as your sole linkbuilding effort.
As the others said above, you can't take links from just one site. These will be links of the same IP, and that's not very good received by Google.
PR7 just by submitting ezine article? ezine itself is a PR6 site. you can get maybe PR3 by submitting few dozen article given that few of your articles will get syndicated nicely therefore having their own PR. i have a few EZA post that gained PR3 in only one toolbar update
you would be better off submitting 1 unique article to as many independent article sites as you can find. 1000 links from one domain doesn't compete with 1000 links from 1000 domains.
It is obvious that you cannot get a PR as high as 7 by just publishing articles or getting links from one website. Get links from varied websites. Get links from different website from different c-class ip. This is only way to go. Just blindly we can not answer this question.
This is interesting. But what is the basis of this structure, i.e. has the creator done any kind of experiment to prove this? or are these just estimates?
I'd say the chances of you getting a PR7 just from submitting to EZineArticles.com are just about zero. EZA is a great tool for traffic (because it's pages can rank in the search engines, I treat it like a pre-lander...) but it's not of much use for building links and PR. I would recommend article distribution services to help with that task.
Just generate a list of blogs/forums and periodically go through them all posting different links, its pretty pointless putting the same link up hundreds of times at the same place