Bloggers sometimes fear posting or re-posting content from other sources on their blog. A successful blogger will not want to solely post information from other sources on their blog without any original postings. However, it is perfectly acceptable for you to put these types of postings on a blog from time to time.
If you are going to re-post content that appears elsewhere online you want to make sure you give proper credit to the original source. You should also introduce the posting with your own words or give some other commentary on the posting.
Every blogger will need to decide on their own when they need to provide a source and when they do not. Typically, if you are going to copy content directly from another source (without paraphrasing) you should give proper reference.
Your followers will appreciate the fact that you are alerting them to content that they may find interesting and it will avoid someone reading a story on your blog that they read previously and wonder why you did not credit the original source.
Videos & Images
Videos and images can be added to your blog even if you are not the creator of the image or video. If you obtain the content from sources like YouTube and Flickr you can safely add the videos or images to your blog. If you think the original poster of the content is in violation of any copyright laws then you should avoid adding the content to your site.
You can contact video sources directly and ask them for permission to post a video clip on your blog.
Some bloggers rather beg for forgiveness rather than ask for permission. That is a judgment call a blogger will need to make directly. For the most part if you posted a video or image that you should not have posted you will be requested to remove it and you should immediately remove it.
Bottom Line about Non-Original Content
The bottom line is that you can add non-original content to your blog when appropriate. Make sure you give proper citations and are not in violation of any copyright laws. If the content is created by and posted by the creator on a site like YouTube or Flickr you should have no problem adding it to your blog.
Be careful but do not be afraid to add non-original content to your blog when you deem appropriate.