Swap-free accounts are also called Islamic because owners of such accounts exercise Islamic religion. According to the rules of the Mohammedan religion, any business transactions, where one of the parties must pay or get an interest from another party, are prohibited.
Islamic or Swap-free accounts allow trading any currency pair and if a position is carried over midnight, a trader does not earn and there is nothing to withdraw from trader's account, regardless of the open position volume. Islamic accounts were created special for Muslims, because crediting swaps and interests is against their religion.
Accounts which are not influenced by swap allow their owners to hold positions as long as it is necessary. In this case the result of trading depends only on the currency rates change during a certain period of time.
Due to this peculiarity Swap-free accounts became popular in both Islamic countries and worldwide. Many Forex brokers provide swap-free service for free.