This is the result of the new promotion system. More details in this post, check the second paragraph above.
Short recap: people can now burn STEEM and pay a small fee to steempeak to have their posts promoted on the feeds. It's something we are still tuning but the main point is that people are burning STEEM, so this will hopefully benefit the whole ecosystem. To promote a post the total amount of circulating Steem is reduced and this should lead to a price increase in the long term.