You can see the rules on http://www.sonsivri.to/forum/index.php?topic=7494.0
at point 23
But of course here are some different opinions about how to share you useful links
For example see http://www.sonsivri.to/forum/index.php?topic=526.msg131278#msg131278
So I think you can share your links in atachement ONLY
for Sonsivri peoples or by PM internal service.
but I don't know how to add the text file to a post so that only members can see it
When compose your forum message you can see in left-bottom page this text +Additional Options...
just click on that text and you can attach any file to your message