Rust-Oleum usually makes excellent paint, so when I was looking at the hardware store for a half pint of gloss black paint to touch up a yard sign a work, I grabbed the can of Painter's Touch Multi-Purpose Latex Paint.  The can stated that this latex was indoor/outdoor long lasting paint on wood, metal and more.  The price was $2.00 less that the Valspar wood paint that I usually use.  I shoulda bought the Valspar.

The paint looked good when stiring, and applied well to the wooden sign.  Cleanup was simple (as it is with all latex paints).  I checked out the sign a couple weeks later and noticed...