An in-depth investigation by the New York Times into buying followers has uncovered a large business and a an extensive list of "clients" paying to add followers to boost their profiles. Mysterious "families of bots appear when an account gets the treatment.
The fake accounts are also stealing genuine profiles and modifying their appearance to possibly evade detection.

Fake followers just make accounts hollow, imho.

It's an interesting article, and the findings will probably come as no suprise to many.

Kristin Binns, a Twitter spokeswoman, said the company did not typically suspend users suspected of buying bots, in part because it is difficult for the business to know who is responsible for any given purchase. Twitter would not say whether a sample of fake accounts provided by The Times — each based on a real user — violated the company’s policies against impersonation.

“We continue to fight hard to tackle any malicious automation on our platform as well as false or spam accounts,” Ms. Binns said.

"Follower Factory" Exposed and Under Investigation [nytimes.com]
It now seems the New York Attorney general is to Investigate the firm involved in the investigation.

“Impersonation and deception are illegal under New York law,” Mr. Schneiderman wrote on Twitter. “We’re opening an investigation into Devumi and its apparent sale of bots using stolen identities.” New York Attorney General to Investigate Firm That Sells Fake Followers [nytimes.com]