I would be stunned if anything like Papers existed for Linux. That said, Unix (and generally Linux) users like to combine simple tools to do stuff that's in th

I would be stunned if anything like Papers existed for Linux. That said, Unix (and generally Linux) users like to combine simple tools to do stuff that's in their control. DropBox would be a good start for syncing, a long text file in emacs which you could drag URLs to and make comments about would be a start. You could build a simple little format like writing 3 *s for a new set of notes on a URL. Then you could use grep to search, wget to pull the URLs down into your dropbox folder, etc. etc. Like I said, though, this is a totally different ethos and result than that app you linked to. You're going to have to want to write bash scripts.