You noticed the CiteULike from here:
CiteULike is a free service to help academics to share, store, and organise the academic papers they are reading. When you see a paper on the web that interests you, you can click one button and have it added to your personal library. CiteULike automatically extracts the citation details, so there’s no need to type them in yourself. It all works from within your web browser. There’s no need to install any special software.