It is ill advised to repost something which is someone’s rip immediately after they did so. This has started a lot of flame wars and is best avoided. I have done so only with the specific permission of the original poster. How long is long enough to repost is a tough question. I can’t think of a hard and fast rule. (although I believe after the original link has expired is fine.)
I am aware that a lot of stuff only circulates because people are reposting others rips. Just be aware such actions can have consequences, aggravation being one of the least of them.
Posting links from other web sites are considered, at the least, a faux pas. Some people feel stronger about it then that. At the very least, reupload it and post the new link. Reposting an actual link has implications about increasing its presence in search engines. I can’t say how true it is, but for this and other reasons, some posters take offense to such practices. (See above)
Posting links to web pages within this community (but not the link itself!) is not a problem, (at least I hope not, I just did that yesterday,) since these links have the original poster’s creds in the post.
Needless to say, there are many other opinions on such matters.
JonC
JonC
Another thing to remember, is that if the link is posted on a private blog, most frown terribly on direct linking. And, many post on private blogs, and not open forums like this, in order to somewhat minimalize where and how the rips are shared. In the end, it all comes down to personal choice. Repercussions can vary from angry comments, to getting banned from private sites. But as far as posting here, aside from the various label restrictions, there are not many actual "rules" you have to follow. Just…common courtesy, I guess. When in doubt, one could always try contacting the OP, and ask if it can be shared.