User generated content refers to material on websites, and occasionally other media sources that is produced by the users of the website. This is different than, for example, a website designed by a company which puts forth material produced by professionals. In user generated content, it is the amateur, in most cases, who contributes the content.

User generated content has become tremendously popular. Some of the most frequently visited sites on the Internet are primarily user generated. This is the case with sites like Wikipedia, where anyone can write an article with sufficient expertise. Other users may evaluate the content, suggest changes, or even make changes. Some material on Wikipedia carries warnings that an author is now espousing opinion, or that certain statements are not verifiable or have been called into question by other users.

No author is paid for contributions to Wikipedia, which makes this type of user generated content distinct from other types. For example, blog sites, where users can blog about any topic under the sun may carry ads, which if clicked on, mean a share of profits for the bloggers. The percentage of profits varies from site to site.

Other times, bloggers may simply be paid a percentage of the profit for having ads on their site, and are paid by the number of people visiting the site. So there is particular impetus to have blogs that will be read by others. This often translates to better blogs being read by a high number of people. Excellence in writing can have its rewards.

Similar to Wikipedia is the now intensely popular YouTube, which has literally thousands of examples of user generated content. However, it should be stated that not all content on YouTube is user generated since it may infringe on copyrights by using songs or video clips that are protected by copyright laws. It may use previously recorded professional material, as with scoring, or in video remixes.

Occasionally, a company will authorize the use of its images or music for user generated content on sites like YouTube. Other companies do not authorize this. Comedy Central, for example, asked YouTube to stop allowing clips from The Daily Show and the Colbert Report. When this user generated content is uploaded, it is usually found and discarded from the site.

One of the challenges with user generated content is that it may be highly inaccurate, and may not be appropriate for the purpose of looking up material to obtain facts. Often the printed, or uploaded word is treated as true simply because it is written. Writers can presume authority or expertise where they have none, and the reader may not always be able to discern the false from the true.

At least for the purpose of research, user generated content should be double-checked against more recognized sources, such as encyclopedias, or dictionaries. This can help eliminate perpetuating untrue material. Often, however, as with Wikipedia, the users themselves are quick to make corrections when material is incorrect.