LiveInternet - крупный сервис дневников и сообществ, авторитетный сервис статистики для сайтов.
The VK comments widget lets you add comments to your site in a matter of minutes. Installing the ... Read more on the advantages of the VK comment widget. 1.
Google+ platform websites integration using the Google+ platform tag.
Let visitors recommend your content on Google Search and share it on Google+.
A pingback is one of four types of linkback methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking to, or referring to their articles.
Open graph description entity tag
Sites who has this tag are verfied by google to use WebMaster tools