I've downloaded all the data they have for s&p 500 many times (I did it with processes, spawned one donwload about every 0.1 seconds). They block your connections if you download too fast.

If they give out csv exports as they do there is no reason why someone wouldn't download them and use them for personal use.

I guess you already know about the CSV download but if you don't, here is a link about it: http://www.diytraders.com/content/view/25/43/

I would however never ever use them in commercial product if that's what you are asking.