"... Two-thirds of this book deals with 'Open Sicilian' positions, in which White plays 2 Nf3 followed by 3 d4. This is by far the most common way for White to meet the Sicilian. White opens more lines for his pieces and attempts to exploit the fact that he will be ahead in development.
Let's take a look at the possible opening moves 1 e4 c5 2 Nf3 d6 3 d4 cxd4 4 Nxd4 ... . White is up in development and can move his pieces more freely. Black, however, has a structural advantage of an extra central pawn, which gives him long-term chances of taking control of the centre. A typical imbalance has arisen. The onus is on White to exploit his lead in development in order to secure an early initiative. If White plays passively or his initiative runs out of steam, then typically it's Black, with the better pawn structure, who enjoys the long-term chances. Thus it's quite rare for a state of 'dull equality' to arise. Often in the Sicilian, if Black 'equalizes', he is already slightly better! This structural advantage is seen in most Open Sicilian lines: for example, the Dragon, the Najdorf, the Scheveningen and the Classical Variations. The major exception to this rule is the Sveshnikov Variation, in which Black accepts pawn weaknesses in return for activity. ..." - GM John Emms (2009) in Starting Out: The Sicilian, 2nd Edition
"... [1 e4 c5 2 Nf3 d6] Almost everybody plays [3 d4]. But isn't this a positional error? I am not joking. I like my center pawns, and I like a [d-pawn] better than a [c-pawn]! I know that sometimes White sacrifices a Knight on [d5] or [e6] and smashes Black before he can castle, but in those games where this has been done, haven't improvements always been found for Black afterwards? Well then, isn't [3 d4] something like a cheap trap? I know it can be combined with purely strategical ideas, but I find it easier to discuss strategy when I have an extra center pawn! I cannot explain where I first got this idea, but I had it before I was Danish Champion and regularly playing [3 Bb5+]. ..." - GM Bent Larsen (1974)
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