With Papers 1.8 you can now highlight and add notes to your PDF. This update also enables you to open PDF files in Papers from other applications (such as Mail and Safari). Library improvements were also added. You can now delete content-less authors and journals, move webpage-only papers into collections and sort authors and journals.
About Nate Hoffelder (11709 Articles)
Nate Hoffelder is the founder and editor of The Digital Reader:"I've been into reading ebooks since forever, but I only got my first ereader in July 2007. Everything quickly spiraled out of control from there. Before I started this blog in January 2010 I covered ebooks, ebook readers, and digital publishing for about 2 years as a part of MobileRead Forums. It's a great community, and being a member is a joy. But I thought I could make something out of how I covered the news for MobileRead, so I started this blog."