1. Anyone can create, edit, or delete Wikipedia articles.
2. Wikipedia articles cannot be considered scholarly, because we know nothing about the contributors.
3. Articles are works-in-progress, meaning changes are constantly occuring to the information. When an article is first published, the information might waver back and forth between viewpoints before achieving a neutral tone. Viewing the behind-the-scenes discussion can be a valuable way of learning about those varying perspectives.
4. Sometimes articles are vandalized, whether for fun, as a hoax, or because the subject is controversial.
5. The intended audience can vary-- some articles are written from a insider's view, with highly technical language, while some are written for a more general audience. This can be both frustrating and valuable depending on what one is looking for, and either way is a warning sign that the information can be inconsistent.