If they are do-follow, your sites will improve their rankings, may increase your PR, and will get some traffic regardless of if they are do-follow or no-follow. If they are no-follow, you will only get some traffic from them and nothing else.
Social bookmarking help you ti increase backlink on your site.so the more backlink come to you the more traffic will you get
Social bookmarking help to get backlinks for your site and if you have a good network they will promote you submissions to their network. I do regular bookmarking and i can see the results in stats of the domain.
it helps in different ways, it can index a new page faster, it can improve keywords optimization (keywords ranking), it can generate traffic, and your backlinks might increase too
Social bookmarking , helps your website keyword get bookmarked. create blogs for your website, and bookmark the blogs helps your website ranking improved and also easily get indexed in Google.
Dofollow bookmark websites always help to optimize your website and specially to gain traffic it always help to gain keyword ranking as well as. this is best source of traffic.
A method of saving and storing web pages in a single online location for future use or for sharing with other Internet users. Sites such as Digg, StumbleUpon and Reddit provide social bookmarking. In a social bookmarking system, users save links to web pages that they want to remember and/or share. These bookmarks are usually public, and can be saved privately, shared only with specified people or groups, shared only inside certain networks, or another combination of public and private domains. The allowed people can usually view these bookmarks chronologically, by category or tags, or via a search engine.
Social bookmarking, is bookmarking a website for visiting later, however one effect of social bookmarking is that it allows you to create link to your specified website, thus this would help increase your backlinks especially if the social bookmarks are dofollow.
Social Bookmarking is a method of saving and storing web pages in a single online location for future use and for sharing with other Internet users. Social bookmarking helps in increasing traffic.
Yes Sure Social Bookmarking is very helpful in SEO purpose. You can get more back link to your website and also it will help to get a good traffic through Social bookmarking.
Social bookmarking is really an effective way of getting traffic for my site and increase my  site pagerank
Social bookmarking is the great way to gain exposure and backlinks as well.. but success always depends upon the fact what you are sharing and how strong your social influence is over social bookmarking websites.