The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
Facebook's Like button is the quickest way for people to share content with their friends. A single click on the Like button will 'like' pieces of content on the web and share them on Facebook. You can also display a Share button next to the Like button to let people add a personal message and customize who they share with.
Google+ platform websites integration using the Google+ platform tag.
Open graph description entity tag