promo-steem is tag on the platform. promo-steem.com is current the beta (a pre-launch) for a site to support promoters. @steem-ambassador is our central account, which will be the one where all promo-steem and steem ambassador announcements will centre. The purpose of promo-steem is to promote the blockchain and the steemit platform across the world, to drive adoption, and raise the value of steem. Hope that clarifies things.