Slashfilm has a new post about some sidewalk chalk advertising Cloverfield showing up "all around" San Fransisco.
It appears this may be part of a larger, overall guerrilla marketing campaign.
The slogan "What is Cloverfield?" matches some promotional postcards I have found (more on that later). Another slogan "What Is It?" is also featured on postcards, as well as mini-posters (like the kind you would see "flyposted" on construction sites in L.A.)
The fact that the advertising began today also coincides with a job listing posted on CraigsList for seasonal help promoting a "NYC Monster" movie from December 21-January 4th (with possible extension to January 18)
I don't know if the viral marketing is winding down, but the street marketing campaign looks like it is alive and huge!
* Thanks to Johnnyutah16 at unFiction for finding the job ad!