this is a well-meaning but badly misguided stance to take. open source is a gift economy, and as one of the "producers" i am more than happy for people to accept the gifts i'm freely putting out there. the reward is getting to feel that i have made their lives better (and that too at no incremental cost to myself). in my role as a consumer, i likewise know that there are people out there happy that they have made my life better. there is absolutely no need to make people feel bad about taking from open source if they don't have the time or inclination to give anything back - that just cheapens the idea of a gift.
now would i like people to contribute by way of code, money or bug reports? definitely. but they should do so because that is a gift they wish to give to the ecosystem-at-large, not out of some sense of reciprocal obligations.
@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) ...
I agree with you. However, just because something isn't implied, doesn't mean it's not a good idea to do it. Charity isn't implied, but it's obvious we should do it in order to help people in need.
We all do open source because we simply love it and want to give a gift, like you said. However, whenever people give me a gift, no matter how bad or good it is, I feel it's my duty to at least say "Thanks!"
It can be a lot more selfish than that though. I contribute to projects because I want to get a better product as a result - even if it's just to test something or document an issue, or providing answers to the community.
For example, the Firefox and Chrome nightlies:
http://nightly.mozilla.org/
http://tools.google.com/dlpage/chromesxs
A couple million hackers can help "upgrade" the Internet every day.
2) Ask/answer questions. You're making it a lot easier for the next guy.
How can I do X in Linux?
http://superuser.com/
http://askubuntu.com/
How can I do Y in Gimp?
How can I do Z in Inkscape?
http://graphicdesign.stackexchange.com/