@Droob : Yes and no, for sure, if you look at the BSD license or the MIT or whatever, there is not reciprocity implied, but if you look at the GPL, there is. If you look at that piece (http://www.gnu.org/licenses/why-not-lgpl.en.html) for example, it's pretty obvious there is a certain "brotherhood" mind implied.
But I think that even if there were no reciprocity implied, giving is more or less morally mandatory (for the bandwidth, hosting cost, etc) ...