string susceptibility

[John Baez]

In some papers on 2d gravity and noncritical strings, the
concept of "string susceptibility" shows up:

http://arxiv.org/abs/hep-lat/9406018
http://arxiv.org/abs/hep-lat/9511029
http://arxiv.org/abs/hep-th/9401137

I need help understanding it.

The idea seems to be that we do the path integral for a given
topology of string worldsheet while imposing a constraint saying
that the total area is A, and get a partition function that's
asymptotically of the form

A^{gamma - 3} exp(-lambda A)

Here lambda is the renormalized cosmological constant (in the
context of 2d gravity) and gamma is called the "string susceptibility".
gamma depends on the genus of the string worldsheet.

I need more physical intuition on this concept of "string susceptibility"!

It might help if I knew why it was called "susceptilibity" -
e.g., how it's analogous to magnetic susceptibility.

I'd also like to understand, perhaps in a very hand-wavy way,
how this susceptibility is related to the conformal anomaly.
I read that if there were no conformal anomaly, we'd get gamma = 2.