While some groups are more discussion and others more question and answer, even in the question and answer ones there is a community of sorts. It is in bad taste to take without giving. Just as you ar e asking help from those who might know the answer to your question, you should help answer other peoples' questions, or participate in the discussion. And if you are a regular, other regulars will re cognize you as a participant anyway. And there are times when it is totally appropriate to post a message followed by something indicating that further discussion should be by private e-mail.
Binaries refer to non-text files, i.e. applications, images, etc.
WWW, FTP, and e-mail are better ways of distributing files. Don't ask for or send files without reading this section. Better to ask for anyone who knows a location where the file can be downloaded to you know. As a last resort, ask that if an yone has the file, to let you know, but to not send the file initially. Then you can followup with those who indicate that they have the file.