I think however that most people (including probably me) are simply not aware what is and is not allowed in this area. I always try to use Creative Commons material and always give credit to the source (please tell me if I fail on that). In most cases I am directing traffic to the source material and thereby helping to spread the work to a wider audience and that is what social media do so well. Anyone who uses this blog and at least gives me credit is welcome to do so!
However I wish that material on the web could be automatically marked to show what the rest of us may or may not do with it. If you post a photo or film or write an article and there was a mandatory field to fill in where you put a Creative Commons licence on it or mark it as copyright then we all would immediately know the rules (Flickr already does this). If I choose to ignore that then I can't say I haven't been warned. If the rules are clear and up-front we'd all be better off. It won't stop the illegal copying but it will help those who do want to stick by the rules.
One tool that helps is ImageCodr. If I find a Creative Commons photo on Flickr I can paste the URL into ImageCodr and I get html code that I can paste into the blog. This produces the photo plus a CC-attribution automatically. This saves me a lot of time but sadly only works for photos on Flickr. A similar tool for other material would be useful.