I usually use parenthesis to add a sort of explanatory sentence in a passage... you know, the typical use (like this, for example). But then, I have seen in articles, and some other places I can't recall now, people using hyphens instead of or sometimes interchangeably with the parenthesis -doing something like this-.
So, is one of them correct and the other correct? Are they equally valid? Or is it just the editor choice?