Why does Google takes so long for the PR updates?
 

The page ranks will take a while to show up in your toolbar. This doesn't mean that they don't have a page rank in google yet, just that google isn't going to show you what they are yet. They update the pageranks in the toolbar every few months. They should be updating it within the next month or so. Also watch the links your posting, they are walking a fine line to comment spam. Also note that they are not linked on this page, so you aren't getting any pagerank boost from posting them here. Google will never disclose the update reasons. But what are your assessments on this? Please share.

Google page rank is to enhance on this listing, article submission, link exchange forum, post a link, for example, social bookmarking and answers.

Google is regularly updated every month to improve the content of the critical updates that happen every six months thus this ought to increase the website's page rank.

Google Rankings could be increased by an effective SEO campaign where you should consider using various SEO techniques like article marketing, press releases etc.

Google is regularly updated every two months to improve the content of the critical updates that take place every six months thus this should increase the website's page rank.

I just checked one of the links in your signature and it is a dofollow link from this forum.