What is the SWAP in the Forex trade? be aware you could be charged or get a bonus

Could anyone tell me how does it work the swap column in the trades on metatrader 4 , I have been charged or compensated(mostly charged) in some trades but I don�t quite understand that

Check out this thread.

http://forums.babypips.com/newbie-island/14363-renewal-rollover-fees-when-market-closed.html

Interest or swap is applied to all open positions at NY close,
long the highest interest rate currency is positive carry.

This is one article I find simple and useful,go through it : How Foreign Exchange Swaps Work - For Dummies :smiley: