Criteo is a "personalized retargeting company" that works with Internet retailers to serve personalized online display advertisements to consumers that have previously visited the advertiser's website With Criteo, advertisers can reach more customers with the same return-on-investment as they get from search marketing. Every da...
The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook