That's good Ben...
I think there's a whole lot of issues about copyrights here... I wonder if this should be discussed formally somewhere else.
With the way we post photos, on web, and especially at dcfever.com, all photographers who publicized their work should understand that everyone can download their work very easily.
It is just as though you have published a book, and everyone can photocopy you photos easily!!
In the academic world, it is a common practice to quote and use materials of others by carefully acknowledging the sources and the authors, using standard referencing systems. For non-commercial purposes, we don't really consider this as "stealing"...
Of course if you download photos from the web and use them for your own purposes, you should ask before doing so.
and Of course you don't manipulate other's work without first acquiring the author's permission. This is considered to be really really rude.
If you post photos and want to have control on how people use them... there are many ways to achieve that (one way is to have huge "signatures" which kills your pics) I think to write a clear statement claiming your copyright on your works would be helpful as well, just to make people aware of what they are doing...
Let's enjoy photography and the ease of sharing them with www.
Do the right things! :)