  We argue that the relativistic Unruh temperature cannot be associated with
the bits on the screen, in the form considered by Verlinde. The acceleration
$a$ is a scalar quantity (the modulus of the acceleration four vecor) and not a
vector. When the mass $m$ approaches the holographic screen, viewed as a
stretched horizon, the shift $\Delta x$ from Verlinde's Eq. (3.15) becomes
$c^{2}/a$ and the entropy variation equals $(1/2) k_{B} \Delta N$, in
accordance with Gao's calculations. Using the Heisenberg Principle we show that
the energy on the causal horizon (viewed as a holographic screen) of an
inertial observer is proportional to its radius, as for a black hole.
