Original Link: http://gigaom.com/2014/01/13/nests-ceo-tony-fadell-explains-why-he-teamed-up-with-google-its-about-infrastructure/

Tony Fadell, in an interview  with Om Malik, on why Nest sold to Google:

I was spending nearly ninety percent of my time on building the infrastructure of the company and I wasn’t able to spend enough time and cycles on what I love doing: products and creating differentiated experiences for our customers. That is where my love is and Google offered to let us focus on that, but with scale that will help bring our horizon closer to us, faster. Google offers to bring that scale to us. For me, ultimately building great products is key.