Product review (5 stars): This Silly Thing Actually Does Make a Positive Difference
The entire concept seems like a scam.  You plug this thing into the wall and it pumps out soothing, moisture-filled air that allows a congested person to rest easier.  I laughed when I first read about them.  But once again, my inner cynic was forced to admit error.  These things help my children sleep when they have a cold.  The filter replacements are easy to install and keep the entire apparatus free of mold and bacteria.  I've been using the same Humidifier for over ten years, simply by keeping it clean and changing the filters regularly.  I mock no longer.