Save and annotate PDFs both directly in the browser or via uploading to the web app. RevNote provides full-text search for all PDFs saved to your RevNote account. Annotations are accessible either in the context of their original document or as isolated snippets of information which can be grouped with similar snippets in ways which help to answer your research questions.
Clip and annotate web pages so that you have access to a full-text copy of each original web article. Not only do you not need to worry about being able to find articles again or whether they even still exist, but you can also search your entire library for snippets of information that were contained in those articles.