I set up a webform which is displayed as a block on a large number of nodes. The webform asks the user if they would like to subscribe to certain node updates - when a certain field changes value and when a new file is uploaded to another field. I therefore have two checkboxes which the user can check, but my problem is - what next? I can fetch the user email, node id and node title via the webform, but what to do with them? How to sort the users based on what they checked? How to display that on their profiles? Should I assign different roles to them? I would then need a role for every node x 2, which seems like overkill. I did quite a lot of googling, MailChimp seems to have many useful features... Any ideas?