Now building a new company: Obvious Corp.

Obvious Corp is an incubator for more ideas like Twitter and the first startup Williams created, Blogger.

The first product it's created is called Medium, which is kind of like Quora or Tumblr, but fancier.

To house all these great ideas, Obvious Corp just leased a massive, 75,000 square foot office in San Francisco's "Flatiron Building" on 760 Market street.

They did the deal with Thor Equities CEO Joseph Sitt, who is best known for his real estate New York deals, but is obviously (!) now getting it done in San Francisco, too.