Hi. I don't quite understand the very last bit of your question, but I'll try to answer the other parts.

Basically astronomers came to realize that
1) Pluto is pretty small (as planets go), smaller than people originally thought when it was discovered, and
2) There are probably a fair number of other Pluto sized objects out near the orbit of Pluto. One of these that was discovered to be larger than Pluto has been named Eris.

Rather than vastly increasing the number of planets, the group of people that decide on the names of objects in the solar system and what categories they should be in (the International Astronomical Union), decided that these smaller objects should not be called planets. Pluto and Eris are now called "dwarf planets" in a category called "Trans-Neptunian Objects" which just means they are mostly beyond the orbit of the planet Neptune.

This does not change Pluto itself in any way, or make it less interesting to us (in fact, to me it makes it more interesting)