S is for Sandbox

What is a sandbox? For me, it's being able to have a world that's developed enough that when the PCs choose to go somewhere, I have a combination of prepared material and improvisation to pull from. So, if I've developed the framework for, say, and elven tree city in a nearby forest, and that's where they choose to go, it's developed enough that it has some flavor of the real, some personality and background. But along the way, I use random tables and/or perhaps a small pre-made scenario I've created that the players can either ignore or interact with.

So, you can't just have this open world with locations and have no plot hooks, right? So what if there's a necromancer's tower? If the GM hasn't thought about what that necromancer is doing at least a little bit, then there's no life there, you with me? Sure, you can wing it, but that can only take you so far. Maybe, just maybe, you want to have something besides "invade necromancer's tower, fight his minions, kill the big bad, and get the loot." Perhaps the characters come across a bunch of imprisoned would-be victims that the necromancer has stored in a dungeon of his tower. What if the necromancer has a loving wife and children that the group encounters? That adds a new dimension to the entire quest, doesn't it?

So what are the causes of railroading which is the opposite of the sandbox?

Perhaps the slippery slope into railroading is dependant on a myriad of factors, as is the case with most things in life. I know that, as a family man in my 30's, my potential for falling into the railroading habit may stem from lack of time to prep for a game. If I don't have time to develop new plot hooks (to me, giving players a lot of plot hooks has to go hand-in-hand with the sandbox).

So, what is your definition of a sandbox? Oh, and here is an interesting Age of Ravens blog post I read about railroading that I wanted to share. Take a look when you get a moment.