WordPress Time Ago / Days Ago (Human Time) like twitter

To print an entry’s time (“2 days ago”):

<?php echo human_time_diff( get_the_time('U'), current_time('timestamp') ) . ' ago'; ?>

For comments:

<?php echo human_time_diff( get_comment_time('U'), current_time('timestamp') ) . ' ago'; ?>

Or if you want a shorter code to implement, you can add a php function in functions.php file of your theme folder:

function time_ago( $type = 'post' ) {
	$d = 'comment' == $type ? 'get_comment_time' : 'get_post_time';
	return human_time_diff($d('U'), current_time('timestamp')) . " " . __('ago');
}

and echo it as:

<?php echo time_ago(); ?>