There's a lot of argument about what is and isn't technically "salsa" and all sides have excellent points, but I suppose it may depend on where you are from. In my area most people use "salsa" as that catch-all term for Latin music - but if you live in Puerto Rico or Cuba or Dominicana than that could be taken as an insult (because of nationalistic pride I suppose).
So with people in my area I usually refer to the music I create as salsa but with people who are more familiar with the music I use the "correct" names, just so everybody can understand what I play.

Salsa has so many sub-genres like guaguancó, charanga, guaracha, cha-cha, timba, plena, bomba, and I suppose even bachata and merengue that you could drive yourself nuts trying to understand "why not just call it all salsa?"
But as far as those other posts, let me tell you that most of them started with me - because I wasn't 100% sure either. I'm a musician and wanted to explore the musical differences (like instrumentation, timing, etc) to see if any of them would be styles I could get into. It doesn't really mean I want to argue my position on if something is salsa, but more to find out how the different styles work and what they sound like.
So the bottom line is:
• if you're a musician it's helpful to know the differences because you can learn most (if not all) of them, have a great time playing, and be able to do whichever one people want to hear at the time. But...
• If you're more into the dance thing, just keep the timing in mind - because if you can't "salsa to it" than it probably isn't salsa (to a dancer lol). And if u ask me it's all so good - it's as flavorful and varied as the salsas we eat =D