Was looking for free social bookmarking tools that are easy and not manually registering and submitting all over and got this on YouTube. BTW if I want to look for any solution I head to YouTube Actually this is a chrome extension called Add This. you cannot call this automatic, it is still manual but this is semi automatic and quite easy and you can get 250+ quality sites regularly updated. So get the instructions here in this video on how to do it !
To add this in chrome simply click Menu
Then on Settings
And then on Extensions
Then scroll all the way down to "Get More Extensions" Click here
In The Webstore searchbox type "Add This Bookmark and Share"
Now you know how to add this to your browser