MOS Capacitance and Performance
The general formula for calculating capacitance is:

\$C=\dfrac{\epsilon \times A }{D}\$

Where A is the area of the capacitor's plates, and D is the distance between each plate. In terms used for designing a transistor, we would make the following substitutions:

\$ C = \dfrac{\epsilon \times W \times L}{t_{ox}} \$

Where W and L are the Width and Length of the transistor, and tox is the oxide thickness (distance between capacitor plates). If we were to scale all three by a factor of n, then we would see the following:

\$ C_{new} = \dfrac{\epsilon \times 0.7W \times 0.7L}{0.7t_{ox}} = 0.7\dfrac{\epsilon \times W \times L}{t_{ox}}\$

\$ C_{new}=0.7 \times C_{old} \$

This scaling doesn't end up changing the channel resistance, because both the width and the length are scaled. Examining the MOSFET drain current expression, we can see that the current (and effectively the channel resistance) is not affected by scaling both the width and length simultaneously.

\$ i_{D}=0.5\dfrac{W}{L}k_{n}^{(V_{GS}-V_{th})^2}\$

As a result, scaling reduces the total circuit capacitance while maintaining equivalent drive strength. Note the (used to) in the Wikipedia article - as the feature sizes have shrunk to about 90&nbsp;nm, this relationship with oxide thickness has become more complicated.