Content writing services (also known as online content writing services and content marketing services) is a category of work that first surfaced in the early 1990s, due to an exponential rise in online activities. Content writing services are firms, companies or group of writers that provide services such as blog writing for websites, web content writing, marketing material content, white papers, research articles, proof reading services, infographic content, social media content, press releases, product descriptions, copywriting services, and many more. Content writing services generally charge a fixed per word rate which is popularly known as PPW (pay per word or price per word). However, many content writing firms also have pricing plans that offer fixed amount of content against subscription plans.