What tools are you using to keep notes on research papers?

Question

Currently I am using evernote to keep notes and thoughts on papers I read on arxiv. What are you guys using and for what reason ?

wannabebarista · Accepted Answer

I use Trello. Being able to link between cards/papers is the selling point for me.

gomangogo · Answer

I use Mendeley but I struggle to maintain a good noting higyene