If the number of subscribers on your list exceeds the limit, you'll receive an email alert." ?>
You can then either reduce the number of subscribers or upgrade your list's limit.
Your account will show the number of subscribers/limit (eg. 1267/1000) alongside an Upgrade link.
You can choose a higher limit and pay the difference by following the Upgrade link.
The difference is calculated on the list's time remaining until it's expiry date.
If an over-limit list has not been upgraded after 5 days, it is suspended.