There could be several factors behind all this: Some women do this because they are proud of their body and want others to admire it. Others do this for the money they can gain by posing nude on some websites. If a woman husband or partner doesn't tell them they have a beautiful body, they could do this to hear from others how beautiful they are. Some are young and just want to earn money so they do this in the privacy of their bedrooms and will normally find a way to distort their faces so people don't know their age. Some do this because it is a simple way to earn extra money and if you are single and can't find a job at least you can pay the rent.