Website using the £ symbol on their website - meaning it may accept payment in this British currency.
Apple Pay payments on the web provides an easy and secure way to pay on websites in Safari. By using Touch ID or double-clicking Apple Watch, users can quickly and securely provide their payment, shipping, and contact information to check out with just one touch.
Google+ platform websites integration using the Google+ platform tag.
The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
Let visitors recommend your content on Google Search and share it on Google+.
Content Security Policy is best used as defense-in-depth, to reduce the harm caused by content injection attacks.
Open graph description entity tag
Sites who has this tag are verfied by google to use WebMaster tools