I don't consider this a particularly controversial question unless it's plainly stupid (Does The Incredible Hulk take place in the same universe as 2001 A Space Oddysey).
For those of you that are unaware, many television shows make reference to other ones which you'd think hadn't happened unless you were aware of it. For instance, The X-Files has an episode where Det. Munch from Homicide and Law & Order: SVU makes a cameo. And both of those shows make even more references to yet more shows, to the point that several hundred television series are connected (if indirectly) to one another. The two shows that seem pivotal in this phenomena are St. Elsewhere and Homicide: Life on the Street. This is often referred to as the Tommy Westphall universe.
Some of the connections are rather weak, but others are full crossover (and yet others seem to be full crossovers, but clearly have contradictory events such as Det. Munch making an X-Files joke as if it were only a tv show).
It's my opinion that such questions clearly deserve benefit of the doubt, and that we should refrain from comments that ask the questioner to justify their question.