I was surprised by XRP as well. Apparently they introduced it as an anti-DOS mechanism, meaning that you have to destroy some XRP to do a ripple transaction[1].

I was surprised by XRP as well. Apparently they introduced it as an anti-DOS mechanism, meaning that you have to destroy some XRP to do a ripple transaction[1]. To me it would have made more sense if each of the accounts involved in a ripple transaction could simply charge a transaction fee nominated in the currency being transacted. edit: it seems that such transaction fees are possible[2]. Not sure why XRP is needed then. [1] https://ripple.com/wiki/Ripple_credits https://ripple.com/wiki/Ripple_credits [2] http://bitcoin.stackexchange.com/questions/7590/does-ripple-ever-charge-proportional-transaction-fees http://bitcoin.stackexchange.com/questions/7590/does-ripple-...