The pumps are because it's still low in supply compared to Steem which has over 300 million coins. Whales are creating artificial scarcity of coins and manipulating the price. Besides, SBD has a market cap of just 50 million dollars. So even a single individual with deep pockets can double it up overnight if he/she chooses to put in a shitload of money into SBD! But as the number of SBDs grow, you'll need more and more capital to bump the price! I heard it was a Korean Exchange last time who bumped the price to 15$... Currently, they'll require double the capital they used last time to pull of that same feat!