I like Mendeley because I can tag, note etc. but it crashes often on Mac. Now I'm trying with another tool - DEVONthink. It has tagging, organizing and apple scripts for exporting from almost all applications. But I have not yet found a way to make my own notes for the clippings or documents.

But 'recalling' is still a manual process. I believe it will remain a manual process for long. I would like a tool to help me though.
Joseph