gistfile1.php

<?php
/**
 * Show Mad Mimi subscriber count w/cache.
 */
 function jm_madmimi_subscribers() {	

	$email = '';
	$api = '';

	// check and get cached subscriber count
	if ( false === ( $subscribers = get_transient( 'mm_subscriber_count' ) ) ) {	
		// if no cache set pull from MadMimi API
		$response = wp_remote_retrieve_body( wp_remote_get( "https://api.madmimi.com/audience_lists/lists.json?username={$email}&api_key={$api}" ) );	
		// if error
		if ( is_wp_error( $response ) ) {
			// fallback count
			$subscribers = 42;

		} else {		
			// decode and format MadMimi API data
			$json = json_decode( $response, true );
			$subscribers = number_format( $json[0][list_size] );

		}
		// store count to expire in 24 hours
		set_transient( 'mm_subscriber_count', $subscribers, 60*60*24 );

	}

	return $subscribers;
	
}