User blog comment:Rupert Giles/Global Navigation Update/@comment-3047208-20141205045145/@comment-11515627-20141205185338

Familiarity, also known as predictability, is a very common practice in user experience development. A good web designer knows how to draw from popular services to build familiar products that will allow a user to feel more comfortable and knowledgeable using a product. This is why you see so many websites that have the same exact wireframe layout.

That said, Wikia could also learn from YouTube in that the latter's isn't as obtrusive. We'll see.