I've posted before about Wikipedia being flat-out wrong.

The most recent one, for example, was about which member of the Kennedy dynasty to be the last to hold public office. Wikipedia lists 2 people as being the last to hold public office, despite there being a decade between when they left office.

Both articles appear to be well-sourced, but one is clearly wrong.

Some Wikipedia articles are as well-referenced as a scholarly paper. For example, the article on "BitTorrent" has 114 references.

Other articles might have few or no relevant references, and there's an automatic banner at the top of the article basically saying "reader beware." I've seen this many times, and I take those pages with a large boulder of salt. Most recently, for example, I looked up the "Vallée Blanche Cable Car" in France. At the top of the page, the reader is warned,

• "This article includes a list of general references, but it remains largely unverified because it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations."

It reminds us of the first lesson in Web Surfing 101: Don't believe what's on a web page unless you check its sources.