If I find a blogs RSS feed could I use it to import the posts from it onto my blog. Or do I need permission? Im assuming that the content might have some sort of protection even if it might be an RSS feed.
Check the Terms of Use of the RSS feeds you are thinking about using. Some are specifically state they can be used in such a way. Some specifically reject such use. If the ToU does not state either way, then check the site that is comes from first. Try to determine the source of the content in the RSS feed. If it is all from the owner of the site (or blog), then contact them and ask. If it is generated by users of the site, you may want to stay away. Depending on the Terms of Service of the site, the copyright for user generated content may be retained by the author. The site may have the right to display it in an RSS feed, but may not have the authority to allow you to use it. All content is copyrighted at the time of creation.
RSS feeds are viewed as copyrighted material. Unless you have specific permission to import and use the actual posts it would be copyright infringement. Most of the news sites prohibit the use of their feeds in this way. Even if the feed doesn't say anything, it would be best to get permission. An absence of a notice doesn't imply that you have permission. From the Copyright what you need to know Sticky
what advantages do the owner of the RSS feed have if someone uses their feed as content in their site?
I'm confused. I saw some sites which with "republished" content from copyrighted rss feeds. Is it illegal. Can they be sued?
If the site publishing the RSS feed/content don't allow the use of the RSS feeds in this manner, then they can take action against these sites since it would fall under copyright infringement.
The safest way would be to automatically rewite them, so they don't resemble to original feeds at all. In general, just because many people are doing it, it doesn't become less of a copyright violation. There are loads of free to use feeds around, but unfortunately almost all of them aren't free to syndicate for commercial use, just for personal, so you'd run into the same problems.
Why would you want to regurgitate content? I mean, if you're doing a local site and you've got local news, weather etc from AP or somewhere, that's fine (usually it'll be a summary or a headline with a link), but full blown articles? Google won't like it, that's for sure.
Too many. The vast majority of new blogs are SpamBlogs. Some estimates are as high as 80%+ of the new blogs are spammers.
Hrm, from what I understand, if you're NOT copying the article in its entirety, (e.g.: you cut it off after first 500 letters, with a link following to the "full article" on the site where it was originally posted), you're not really breaking any rules. At least that's what Google claimed in their defence for re-posting parts of articles in Google News... But just as Google, to be safe, put a link on your site where ppl would be able to ask you to remove their feed if it bothers them. I think this way it's pretty safe....