The module ShareThis integrate social bookmarking utility on the node types you want.
Download and enable the module.

Go to Configuration - Web services - ShareThis

Choose a button style.

sharethis display.png

Choose your services and extra services

sharethis services.png

Configure where the ShareThis widget should appear.

sharethis context.png

The advanced settings canusually be ignored.

sharethis advanced.png

Save configuration.

sharethis result.png