The practice of using 'hidden' links rather than the page's actual title, so that words or phrases are highlighted. This makes it easy to insert links without disrupting the flow of the narrative, but causes viewers who compulsively click while reading to lose track of a long article. Blogs are notorious for this, rather than putting links at the end of an article. See Text Formatting Rules for how to make one. If the linked article is completely irrelevant to the displayed text, then it's a Sink Hole. Sink Holes are discouraged. Not to be confused with a Plot Hole, or those things in the road.