The stated core goal of MIRI/the old SIAI is to develop friendly AI. With regards to that goal, the sequences are advertising.
Kinda... more specifically, a big part of what they are is an attempt at insurance against the possibility that there exists someone out there (probably young) with more innate potential for FAI research than EY himself possesses but who never finds out about FAI research at all.
Many people have an incorrect view of the Future of Humanity Institute's funding situation, so this is a brief note to correct that; think of it as a spiritual successor to this post. As John Maxwell puts it, FHI is "one of the three organizations co-sponsoring LW [and] a group within the University of Oxford's philosophy department that tackles important, large-scale problems for humanity like how to go about reducing existential risk." (If you're not familiar with our work, this article is a nice, readable introduction, and our director, Nick Bostrom, wrote Superintelligence.) Though we are a research institute in an ancient and venerable institution, this does not guarantee funding or long-term stability.