I get home from work tonight and unload some groceries and when I came back out of the house I noticed a silver dollar sized wet spot on my driveway that is right underneath the muffler in back of the rear end. The 'wetness' was coming out of what looked like a small hole in the muffler. I've never noticed this before. Do I have a hole in the muffler or is this normal?

 

Most resonators and mufflers have a weep hole for just this reason. It helps prevent internal rusting.

 

Yep, I have it too.
I thought it was a hole at first but it's too perfect so I decided it was part of the design.

Ford Super Duty Diesel - YouTube

 

Not a new concept. Muffler weep holes have been around for a very long time.

 

Yes, it's normal. But, yours is not at the bottom, so you should actually drill on at the lower end, at the bottom, so it always pushes out the moisture. By the look of that pic, your carrying several cups of water in there and it will rust fast as a result.

 

That's where Ford put it.
Mine's the same.