“Playing the government off newspapers, and newspapers against each other, still does not compare with the power of the World Wide Web.”

Source: The Note Book of Elbert Hubbard (1927), p. 142.

Unkempt Thoughts (1957)

Letter to Colonel Edward Carrington (16 January 1787) Lipscomb & Bergh ed. 6:57
1780s
Context: The basis of our government being the opinion of the people, the very first object should be to keep that right; and were it left to me to decide whether we should have a government without newspapers, or newspapers without a government, I should not hesitate a moment to prefer the latter. But I should mean that every man should receive those papers and be capable of reading them.

Source: The Economist, 1st October 2011, p. 89

Source: The Bed of Procrustes: Philosophical and Practical Aphorisms (2010), p. 21

"On the Cryptic and the Elliptic"
All Things Considered (1908)
Context: For fear of the newspapers politicians are dull, and at last they are too dull even for the newspapers. The speeches in our time are more careful and elaborate, because they are meant to be read, and not to be heard. And exactly because they are more careful and elaborate, they are not so likely to be worthy of a careful and elaborate report. They are not interesting enough. So the moral cowardice of modern politicians has, after all, some punishment attached to it by the silent anger of heaven. Precisely because our political speeches are meant to be reported, they are not worth reporting. Precisely because they are carefully designed to be read, nobody reads them.

As quoted in Morrow's International Dictionary of Contemporary Quotations (1982) by Jonathon Green

No known source in Twain's works.
The earliest known source is a Usenet post from November 2000 https://groups.google.com/forum/message/raw?msg=israel.francophones/j_b0peHVcJw/YN5cG6Pdk6QJ.
Disputed