Steemd.com is the block explorer of STEEM where you can keep a detailed track of your activity on steemit.com as well as use to monitor your STEEM POWER mining progress. It seems however that the website went down a while ago and is currently not opening, so at the moment you cannot keep track of the extra statistics and information that it provides.
Hopefully the problem will be resolved quickly and the website will be back online shortly, but meanwhile don't you think it is a good idea to have more than one such block explorers for STEEM just to have a backup if there are issues like that in the future?
It is always a wise idea to have a backup in case something goes wrong…