The Tropical Zodiac (the one we all familiar with) is based off of the vernal equanoxes and is based off of the sun's position on the planet, rather than being based off of the actual positions of the constellations in accordance to birth (and other activities).
The Sidereal Zodiac (the one which is older, and made by the Mayans) is the zodiac which is actually based off of the positions of the stars in accordance to events on Earth. This is the zodiac which features the thirteenth house (sign) of Ophiuchus.
Take me for example. I'm a Tropical Leo (Sun sign) and a Sidereal Cancer. Does this mean that I am simply Cancer and no longer a Leo? Of course not! If you have been reading the articles like I have, I could see how you would believe that it is a change, rather than a simple aspect almost no one knew about. The only change is that the Sidereal Zodiac has been brought to attention. It is not a farse, a joke, or some madman's imagination. It is something as ancient and valid as other topics in metaphysics and Magick.