Firstly they are
not actually towers, they are interceptors, which are basically just computers with an antenna, often referred to as "StingRays".
http://www.meganet.com/meganet-produ...erceptors.html
Stingray devices are real enough, and they are used by law enforcement. But this does not equate to fake cell phone towers spying on all Americans. Stingray usage dates back several years:
http://online.wsj.com/news/articles/...83112723197574
More likely the Yahoo article above is just a public relations exercise for the manufacturer of the "Cryptophone 500", which supposedly detected these 17 interceptors. Online commenters have suggested that what is being detected is likely just secure government private networks, such as might be used at military bases.
So, a business insider writes an article harping on legitimate current fears about eavesdropping and promotes bogus conspiracy theory to sell his product.
Shocker.