http://www.recode.net/2016/9/1/12762774/google-shelves-project-ara-smartphone
http://www.theverge.com/circuitbreaker/2016/9/1/12762236/google-project-ara-suspended-modular-phone-report
With the internal structure of Google recently changing, so has Google's hardware division. As the article mentions, Google has begun to merge its different hardware projects into one division, under the helm former Motorola President Rick Osterloh. He has decided to cut loose ends, seeing Ara as one of them.
I see this as yet another great idea, or at least an opportunity for innovation in a increasingly stale handset market that has gone to waste. Ara has now seen the "suspension" fate that projects like Glass or Pixel saw. Glass to its own end was a fantastic idea, but was barred by public adoption resistance, mainly because of the negativity that the camera received. I'll also note that Glass was something that I see many people asking from VR now; a tetherless, AR experience. These are quite frankly stupid reasons, and I assume that Google thinks Ara would've hit the same snags. Hopefully all of these projects are brought to life once again someday, or at least licensed out to other manufactures.