Warning: session_start(): open(/var/lib/php5/sess_n420u9hs64mmajkord0urlbdd5, O_RDWR) failed: No space left on device (28) in /var/www/clicktotweet.com/www/index.php on line 5 AOV for Instagram referrals = $65 vs $55 for Facebook, $59 Pinterest http://elstcp.at/1ApOXBm via @getelastic