One of the things people used to say about Microsoft was that their strategy was to “embrace and extend”. They would take someone else’s idea, improve it and take over a market.
While I am not advocating taking over another bloggers market, this embrace and extend idea can be a useful way of looking at content creation. Take a good idea and make it better, more accessible, or in a new format.
Building on top of ideas can provide a fresh perspective and clarity, so can be valuable to your reader, valuable to you as content, and valuable to the original as traffic.
As an example, Don Campbell has taken my Creating Flagship Content ebook and made a mind map of it. Mind Maps are a great way of taking notes about a subject, so the download compliments my work and makes the ideas accessible in a new way.
Instead of just reporting what someone else has said in a blog post, maybe with a quote or two, consider how you can extend the ideas they have put forward. That way you are providing new and additional value over and above a useful link and showing your feed is more useful than as a mere aggregator.