Hotlinking is if you point at a link and a million people rush over to look at/download and the person's bandwidth disappears in a woosh. It's why if I put say a pic of RB up, I save it to my own space and point to it there, so the bandwidth drain is on me.

Of course, some people don't want you copying the pix, so in that case, you link..it's a minefield!

It's also bad to watch something on someone's site instead of saving to your own computer; if you only watch a vid once, it's the same use of BW as if you downloaded it, but if you keep on going back to watch it there, it mounts up for them.