The fact that wiki is well known and used by everyone may be a problem...If you think about it wiki is open for anonymous yet obvious editing. But is it reliable. It is assessed a lot. But even the makers admit that Wikipedia is a bit misleading. There have been reports that Wikipedia contains poor spoken language.
I wrote for WP before.
WP has a long list of rules regarding verifability, original research, and citing your data to a reliable resource. It also has thousands of people constantly reverting bad edits and placing a mark on the editor's IP adress.
I've had this happen before. I wrote an article about my local internet provider; taken down within minutes for being "not notable". Edited some other articles, and got my account suspended for "non-verifiable sources" and "original research".
Have use it so many times before and it didn't give me any error assessments when i used it as references for my research topic. It is vetted from the reliable source of primary and secondary books and articles. So, it is the same as referencing directly from the source itself but because of there's too many information in the primary source, that's why people want to access directly on only the meaning of terms rather than have to scroll down the online books or articles just to find the definition or for straight-forward answers.
Wikipedia is a brilliant source of knowledge and can be easily accessed by all, for the likes of students and people seeking facts it is an excellent way to research and can be trusted. Wikepedia can be accessed by anyone and edit by anyone - true, but majority of the hundreds of thousands of articles are accurate. The Internet in general can be classified as an unreliable source of information, but wikipedia is reliable.
Although wikipedia is a worldwide known website, to me it is not a reliable website. I took several courses on academic research and Wikipedia is not totally reliable when coming to get informed about a topic, people can use it as a beginning point to get a mere reference about a topic, but we can not assume that what is published in this website is totally true. Any person can modify any article without knowing enough about it, there are lots of articles that do not have references to sources where the information was taken from and this is plagiarism, that are lots of incomplete articles... That does not make a website reliable. As said before, if you want to know about a topic, you can get some ideas from Wikipedia, but you better look for true reliable websites.