Not only does it make the rug stay in place on hardwood floors, but this rug pad is thick enough that my rug feels more luxurious and comfortable underfoot.  I especially noticed this when I dropped my phone under the couch and knelt on the rug to retrieve it.  I realized then that kneeling on the rug didn't hurt my knees like it had before I purchased this rug pad.  It also provides a bit of sound-muffling on the floor, which was an unexpected bonus.