* Only when your social bookmarking sites use 'do follow' attribute, search engines will be able to follow the links and give credit to that link. In other words, your link will be counted only when it comes from a page with 'do follow' attribute.
* Second important factor that you should take into consideration is the reputation or popularity of the social bookmarking site.Social bookmarking sites with good visitor traffic will be a good source of traffic to your website.

Yes i agree with you,site should be do follow in which you are doing social bookmarking.

thanks for your information here after i follows this while selecting my book marking list

Hi
High Pr and fast approval are good .

hi.
For social bookmarking sites you can use do follow sites, high page rank sites easily increase the page rank of a site.

Submit your website in High page rank social bookmarking website and also make sure that submit website in most related category social bookmarking website. 

I select social bookmarking sites by seeing moz rank and domain authority.

what are your fav bookmarking sites?

Always select do-follow sites that has high page rank.

Hi,
Other factors are:
- High PR
- Relevant category
- instant approval

Web site, submit your site high page rank and site social bookmarking social bookmarking website to the delivery category.

If I select my social bookmarking site then first check two main factor 1. page rank  2.  Dofollow / nofollow . If  social bookmarking sites pagerank is high and dofollow. Then I check which types of post in this social bookmarking site. After these all things I select my social bookmarking site.

Always select high page rank with dofollow Social bookmarking sites

According to me Social bookmarking is becoming extremely popular on the internet. With so many internet users today and so many wonderfully informative websites around, Social media does more than provide you with articles and websites that interest you.

Hello...
Social book marking sites provide a good source of back links but you can choose social book marking sites with unique IP address.Submit your Title,Description,Trackback Url,Meta Keywords and category Properly.....

We choose social media networking sites for powerful link building. Face book and Twitter have more users as compared to  Myspace, Google +.

I agree. Social bookmarking is really good way of link building.

Social media sites help to improve ranking on search engine so must be selected those sites which keep 3 or more page rank. 

High PR doesnt seem to be a ranking factor much any more. Social sites with RELEVANT CONTENT seem to be the way forward