TechCrunch uses Socialite.js script can for displaying social media sharing buttons with lazy loading feature. Lazy load simply means that the real js sharing buttons comes visible only when you hover over to them, this way you increase your page loading speed up to some extent. This tutorial is on a free WordPress plugin that enables TechCrunch like social sharing buttons in your self-hosted WordPress blog.
So first of all install and activate WPSocialite, after activation visit its settings page on admin area and set the various display options like mode, class, style and position etc.
Other than this you may also use its Template Tag or Shortcode for displaying lazy load sharing buttons.
<?php $args = array( 'size' => 'large' //choose which size buttons to display. 'url' => 'http://google.com', //use this to override the url that is sent to WPSocialite. Not recommended to use in loop. 'button_override' => 'facebook,twitter-share,twitter-follow,pinterest,linkedin,gplus' //used to override buttons that are displayed. Add and remove as needed. ); wpsocialite_markup( $args ); ?>
[wpsocialite size="small" url="http://google.com" button_override="facebook,twitter-share,twitter-follow,pinterest,linkedin,gplus"]