Pretty much every game I download on my iPod sends me daily push notifications 'Don't forget to play today for your reward!' or something along those lines. My idea was a new set of achievements (preferably that can only be triggered on the first character of each master account) that would mimic the hugely successful set up that apps have. Something along the lines of:

- Log in every day for a week

- Spend an hour online for 5 consecutive days

- Play for a week/month (not limited to just one account)

Similar to push notifications, I think emails regarding all achievements might help in user retention too. Although the gifts are a great touch, they're ultimately random. Perhaps reminding them specifically 'Don't forget; only 1 more day till you can claim your latest reward!' would be more beneficial than random gifting?