It's been stable at around $1 since i've been on here. The idea is that when STEEM is low, you can purchase it using SBD (to reflect the US dollar), then when STEEM is high, it could be sold back to SBD.

It only works when SBD stays stable in price, around $1 USD. Now, when we earn some SBD, it's in our best interest to immediately sell it for STEEM at about 3:1 or hold on to it in case it increases in value even more! @ironshield