Official Site: http://us.battle.net/sc2/en/blackstone/login Password is Y7_$0>0k_3<$m
Reddit Topic: http://www.reddit.com/r/starcraft/comments/17zgcf/blizzards_newest_websiteproject_project_blackstone/
This seems to be a unique form of advertising for Heart of the Swarm, the characters involved even have Twitter accounts.
https://twitter.com/Adjutant3327
https://twitter.com/LeahAMartine
https://twitter.com/RedellQuinton
https://twitter.com/HelekBranamoor
https://twitter.com/PamelaGFoster
https://twitter.com/VeraLangridge
https://twitter.com/TalenAyers
None.