Forum Moderators: open
People like to do what they do, and if you try to alter those habits you will alienate some level of visitors. I often open links in new tabs on FireFox so I don't lose my place in the other page. I also tend to close sites that dictate how I use my browser, hint hint.
Two, I'm a firm believer of SAVING files one will reuse. I think this would be rather nifty conciding I would prefer not to have bandwidth burned by peopole who keep coming to the site to download the same files. I had one guy burn over 1 GB of bandwidth a year ago because he kept watching the same video over and over but something kept clearing his cache. I forgot which apche code (304?) it was but the point is that a GOOD designer won't force you to do something lame ... like tell you that you have to turn off Adblock or other adblocking software or you can't see their site.