Understanding working principal of social bookmarking

Hi all from this thread and all the replies on that thread http://www.sitepoint.com/forums/showthread.php?782494-What-is-and-How-to-do-Bookmarking I ahve come to know what is social bookmarking.

But I have a question how does it helps to get high PR - I mean, how it is beneficial to SEO? A confusion develop in my mind that if I just register to a social site and bookmark my site but I do not have any friends in my social account - is it then helpful; bcz how others (as I have no friends in the list there) will got notified about the site that can generate traffics to my site?

I think I am able to make u understand my confusion. Please help me to get it clearly.

Social media sites will do little, if anything, for your search rankings. They won’t get high PageRank. They won’t pass much, if any, googlejuice. The reason for this is that Google will not pay them much attention as they’re too easy to manipulate.

The reason for using social media sites is to get direct traffic from real people clicking on a link - not to improve your search position.

I am not clear in this topic, since i will tel my opinion. When ever you posted any posts google will go through it, friends is not necessary for your profile…

Its just my opinion, i am not conform in it…

There are very few social bookmarking sites were I have seen any substantial results so I am with you wha is the point?

The working principle behind social bookmarking is to drive targeted traffic to your site everytime you are adding new content. Using something like ping.fm allows your content to be sent out to multiple social sites all at once. Where the work actually comes in is building up those social networking sites with friends and people that are interested in your niche topic.

social bookmarking is a method for web users to store,organize, search and manage, bookmarks of webpages on the internet with the help of tags or the keywords on sites such as Digg or stumbleupon, delicious buddybookmark. It play a viral role in promoting your website. It is a easy method to generate actual back-links for a website. It provide one-way backl-links.