A new "currency" has been introduced within the ESL for contents that are liable for costs: PD. The abbreviation stands for "Premium Days", the amount of days a Premium Account is valid. So if a stream costs 10 PD, exactly 10 days are deducted from your active Premium Account.
This means that your Premium Account is comparable to a bank account that you need to refill regularly. If a non-Premium user wishes to view a stream, he buys some Premium Days, fills up his account and can pay for the stream.

A PD does not have a fixed value as one can receive discounts e.g. for team payments. One PD has a value of between 3.33 and 6.66 Cents. This means that watching the stream of the EPS finals (~2+ hours) would cost about 20 PD - or between 66 Cents and 1,30 Euros.