What is social bookmarking?

?  ? Sorry if it sounds like a stupid question but i am a bit confused about the actual and 100% accurate meaning of social bookmarking.Is social bookmarking is all about creating backlinks for SEO by posting your site links on social networks like facebook,twitter?Or how we can differentiate it from the article writing required for creating backlinks for your site in order to higher rankings in search engines?

it is now only useful for SEO but can be used also as personal bookmarks or a library of your fav links which you can't remember since its too many to memorize. Like you dont want it to be remove from your firefox bookmark when you uninstall the browser.

Such way is for organization and storage for bookmarks that can be use in online researches.This is sometimes arrange using informal tags.

Social book marking is sharing your bookmarks publicly through social bookmarking sites like stumble upon and delicious. It also helps to gain one way back links.

Socialbookmarking is a process of sharing your bookmarks publicly via social bookmarking sites which is one of the most effective means of  gaining back links for the website, which will inturn improve the sites ranking in search engines.

Social bookmarking is a SEO things

Twitter was able to increase the reverse link from the site ranking in search engine article writing required

Social bookmarking is a method for SEO.

in bookmarking users save links to websites.
and in social bookmarking people save links to websites for friends and other people.

Social bookmarking is very important for any website's rank......

Social bookmarking plays a very important role in search engine optimization.