Just listened to the podcast of the cigar show and was surprised to hear that nobody knew the difference between a hydrometer and a hygrometer. It's a shame Doc wasn't there, because I bet he'd have had the answer. The chat poster was gently pointing out that the guest was making an embarrassing mistake.
A hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids - that's what we brewers use (unless you use a refractometer). The device on a cigar humidor is a hygrometer, which is an instrument used for measuring relative humidity. A hygrometer would be no help with brewing beer, and a hydrometer is useless for keeping cigars fresh.
-JAI