i.e. using open source under the published license? Look, I'd prefer that everyone using open software supports it with public patches, but if it's not under A/GPL or something, then clearly the authors weren't so worried about it. If you don't like others using your work without publishing their changes, use A/GPL. If you don't like others using your work without paying you, go with shared source (and accept that you're writing proprietary software) or use a noncommercial license or something. But don't publish something and then complain that people used it under the exact terms that you published it!