The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.
Chrome for Android, since version 39 supports the "theme-color" meta tag to allow websites control the background color of the tab's UI header.
Google's hosted library for web fonts. Allows websites to choose and use fonts from a free, wide variety of fonts.
Typekit is the easiest way to use real fonts on the web. It's a subscription-based service for linking to high-quality Open Type fonts from some of the worlds best type foundries.