Google confirmed on Tuesday that it has come under the scrutiny of both the Department of Justice and a number of state attorneys general over a proposed deal with book publishers to put millions of books online.

For all the discussion and debate about Google's controversial (and potentially anti-competitive) plan to digitise millions of books, little has been known about how the company is actually doing it.

The audacious plan involves scanning many millions of books, through a system that Google has said is light years ahead of the flatbed scanners we're all used to - systems that inevitably proved unreliable or destroyed the books they were intended to preserve. But Google's.

Google (GOOG) is facing a rising tide of discontent about its market dominance. Take the ongoing lawsuit over its effort to digitize millions of books. Google reached a tentative settlement with angry book authors and publishers earlier this year, but antitrust enforcers now are considering whether the agreement gives the search giant monopoly rights to commercialize a big chunk of that content.

Separately, advertisers are also up in arms. They say they have no bargaining power because Google controls so much Internet search ad real estate—more than 70%, according to the U.S.