To be honest, when I see my pictures being used by someone else it brings great joy. I have told this to the handful of people who ask whether if they can use my picture for something or the other. But it was just yesterday that it clicked to me that I was publishing my pictures with all rights reserved. Never took this seriously, until a friend pointed this out to me and asked me to walk the talk.
So now its official, I have switched all the pictures that I have in flickr to Attribution Creative Commons. That is the most accommodating of the 6 license schemes available in creative commons. You can have a read about the six license schemes here, http://creativecommons.org/licenses/
Technically speaking Attribution Creative Commons allows even the commercial usage but requires the user to acknowledge. In my case you do not need to do that, just use it and if you really feel like showing me just send what you have done for me to see.
Btw I gave myself a gift by getting flickr pro account. Lets see whether if I would get value for money.