Right now, the overall following limit is 2000 and this is applied to all subscriptions. Please note that is a measure designed to reduce stability issues related to following a large number of accounts (e.g. problems loading your Stream, followings page etc).
You may also notice a restriction on the number of accounts you can follow within a day. This can be explained by the following:
You are following a lot of accounts in a short time period
You are following a lot of the same accounts that you recently unfollowed
If you keep getting warnings about this activity, you will be blocked. Please note, no matter what subscription level you have, we cannot manually remove any blocks - this is to ensure fairness for all of our users.