Yesterday was the birthday of my website, I have achieved the milestone of an average of 400 visitors from Google, yet my pagerank = 0
Do you guys have an idea on how much traffic generates PR1 , 2 , 3 etc ... Please share your data
There is no correlation between traffic and PageRank.
Google cannot track traffic for most sites and has wisely keep traffic out of the metric mix. Having said that, there are some metrics to pay attention to: search engine result page (SERP) click-through rate (CTR), Bounce Rate (back to SERP), apparent time spent on page, apparent time spent on site. Google cannot fully determine how much time is spent on a site or page, but can extrapolate an approximation based on some metrics. What is most important from a SERP point of view is the Impression/CTR/Bounce Rate ratios. Keep this in mind.
In fact, do not look for Google to issue PageRank scores. Google has retired the PageRank metric as it applies to sites. SiteRank replaces PageRank and is not a publicized metric. The simple answer is that it caused confusion and complaints.
SiteRank is related to the bulk of the metrics that Google keeps. A major part of this is TrustRank. I just happen to be creating (as we speak) a webpage that lists the metrics that effect TrustRank and it is a significant list of metrics.
If you are interested in improving SiteRank, you will will need to focus on Trust metrics for your site. Part of this is site age, quality registrar, quality host, contact information (use mark-up), good up-time ratio, remaining off of black lists, and so on. The list is far too large for this format.
As well, use trajectory to your advantage. Part of this is adding and updating content (freshness), creating high quality inbound back links, high quality organic inbound back links (created by real humans - not you) - you will not have much control over this, planning and covering topics/sub-topics that broaden your keyword reach, social signals (I like Twitter), and so on. Keep one eye on toxic links and very cautiously and selectively disavow particularly bad links. Generally this is an action that should only be taken under extreme conditions.
There are two things you do not worry about: PageRank, and keyword density. Yes. Use keywords and plan your keywords carefully, but do not narrowly focus your content too much by optimizing for too few keywords. Long-tail keywords offer more traffic in the long run. Over optimizing a site for select keywords, limits the opportunity to rank well for long-tail keywords.