I wouldn't do one of the ones that has commercials on TV, but the ones through real, standing universities should be fine. I'm taking one through the USDA. It's actually a class in indexing (as in writing indexes for books). That's a little out of the normal realm of the USDA, but there aren't really any universities that teach graduate level classes in indexing, so they offer it. They can't give degrees, but the credits will transfer if I ever decide to get a Masters in technical writing.