I agree. A signature in the lower corner is I think quite appropriate and useful. I do not really consider that a watermark, as I find watermarks really annoying and will not even look at images covered with protective writings.Nothing obnoxious just my signature in the lower right corner.
Not sure what your goal is. What problem are you trying to solve? If you want to ensure that your photos cannot be used by anyone else, the best thing is to not post any images anywhere on the internet.I have been told that any watermark can be removed....perhaps the best way is to deposit the photo with a reputable company ?