I certainly agree with doing it.
I tried for years to keep check on my photos - seeing them posted all over, some with my name cropped off. I finally decided to just go along with it, I put my name on it but not always in an obvious location. Sometimes I will put it in at a slightly different color than the background, or embed it in the image.
It's more of a tracking thing for me now than a keep it under control.
If you see pics with "Tim Ahlborn 2015" that means it's my photo and I was the photographer. If you see a pic with "Tim Ahlborn Collection" that means that someone gave me the photo from their collection, or I bought a photo collection, or something along those lines - not claiming ownership or being the photographer, but again just tracking the photo, some personal satisfaction seeing the image get spread all over, and it allows me to correct folks who claim that the image was theirs or other incorrect information.
I used to get my knickers all bunched up about it, now I just sort of chuckle - especially when I see a FB post that someone mistakes one of my model truck photos for the real thing.