If your feet sweat, you may have stinky feet and suffer from foot blisters; if you are a runner, these can be especially problematic.
"The feet have approximately 250,000 sweat glands and produce approximately as much as a pint of moisture a day." according to John Vonhof's book Fixing Your Feet: Prevention and Treatments for Athletes. This book is so popular that it's in its 4th addition.
Following is a excerpt from the book. It's a runners contribution of his remedy for sweaty feet...
"Mike Palmer has worked at resolving blister problems related to sweaty feet. He wears sandals as much as he can to keep his feet dry during the day. A couple of weeks before a 100 miler, or an ultra of 50 miles or more, he uses alcohol at night to dry his feet. He finds coating his feet with Tincture of benzoin dries the skin as well as providing a protective coating. This has worked well for him. Before a 100mile run, if the weather allows, he tries to walk about a mile barefoot about a month or so before the race in an attempt to further toughen the skin. Then before the run he uses an absorbent foot powder and puts dispensers of this powder in his drop bags at every point where he will make a sock change."