We are going to start accepting Dash and other crypto currencies, in addition to Bitcoin.
They will purchase the same amount of ad credits as the amount of Bitcoin that their alt-coin would have purchased. In other words, one ad credit is still pegged to Bitcoin and they will get whatever exchange rate their coin has with Bitcoin at the time.
There will not be any option to redeem them as alt-coins, however. Each ad credit will continue to be redeemable for their equal amount of Bitcoin or spendable to purchase advertising.