I am planning to create a web service that aggregates existing content available on various websites and present it in a manner that is more user-friendly.

There is no information available on the copyright status of the content and it is freely available on forums, esnips, google, etc. I was wondering if I could just use this content at my website without violating copyright rules.

On the other hand, I am planning to request users to suggest content to form part of the web service. For this case, I assume, the content ownership is not mine and the copyright liability belongs to the poster.

Looking forward to your replies.