If you can produce good quality editorial photos, you could probably make a little money. There are so many other people trying to do this that you need to produce photos which "stick out" and are more prominent than your competitors. You need a certain amount of luck also, because when someone searches for an image with a keyword on a stockphoto website, several pages of images may appear which the user has to trawl through, and you could be bottom of the list. This is why tagging with relevant keywords is so important. Don't try selling photos of pretty flowers or your pet. Many of the agencies will reject these (unless "Spot" is doing something spectacular!).
Personally I've only made about $100 selling photos. One photo in particular has sold about 10 times, this was a still life image of a group of electrician's tools. So possibly this was for editorial use on an article about DIY or similar.