From Pierre Bayard's How to Talk About Books You Haven't Read (or The French Way):
The notion of skimming or flipping through books can be understood in at least two different senses. In the first case, the skimming is linear. The reader begins the text at the beginning, then starts skipping lines or pages as, successfully or not, he makes his way toward the end. In the second case, the skimming is circuitous: rather than read in an orderly fashion, the reader takes a stroll through the work, sometimes beginning at the end. The second implies no more will on the part of the reader than does the first. It simply constitutes one of our habitual ways of relating to books.
But the fertility of this mode of discovery markedly unsettles the difference between reading and non-reading, or even the idea of reading at all. In which category do we place the behavior of those who have spent a certain amount of time on a book - hours, even - without reading it completely? Should they be inclined to discuss it, is it fair to say of them that they are talking about a book they haven't read? The same question may be raised with regard to those who, like Musil's librarian, remain in the margins of the book. Who, we may wonder, is the better reader - the person who reads a work in depth without being able to situate it, or the person who enters no book in depth, but circulates through them all?
From John Sutherland's How to Read a Novel (or The English Way):
Judges of fiction prizes are routinely asked if the 'read them all', and are as routinely misreported on the topic. It is hard to reply, accurately, because 'read' is such a blunt term. Is studying Emma for A-level the same reading act as skimming the latest Jeffrey Archer in the airport departure lounge with the aim of finishing the thing before boarding in forty minutes? 'I've read the newspaper,' we say, meaning, 'I've glanced at the headlines, scanned the letters page, decided not to bother with the editorials, looked up the soccer results and taken in my favorite columnist'. You can gut novels the same way - but it is hardly 'reading'.
Upping the reading speed helps. Silent reading is, although no one is quite sure, a relatively late arrival historically. The Venerable Bede was regarded as prodigious in the seventh century in that he could read without moving his lips and was therefore faster than he could speak. What Bede has worked out, evidently, was the amazing buffering capacity of the brain: that it can take in verbiage fast and play it back to the mind's ear at the right, slowed-down speed. Larger 'eyebites' and various other 'speed reading' gimmicks were promulgated in the speed reading mania of the 1960s - when information overload first became a worry. Unfortunately, there are absolute physical limits to the rate at which one can read. Few will reach them, but no human eye will exceed them, any more than any athlete - however well trained and drugged - will run 100 meters in three seconds.
Nowadays, it seems to me, something like the 'surf and zap' approach is required. As with satelite TV and its hundreds of channels, one has to skim through, stop where it seems interesting, zap the commercials and other impertinent material, concentrate from time to time where the offering seems genuinely interesting.