I'm ashamed to admit that I just discovered the "subscribe to tags and receive email notifications" mechanism. Until now I always imagined people just browse for (new) questions that they can answer, especially since being a fast gun makes a difference.
It's not the first time similar issues are brought up on Meta (see for instance here and here). However, I have a feeling that both the user interface and the community have matured significantly in the meantime, so I'm guessing by now people have clear preferences for one way of working or another.
To what extent are answerers "actively" engaging in SO (browsing for questions, with or without the help of favourite tags or other such filters) versus "passively" waiting for new questions to present themselves (e.g., via email, where the earliest one can get notified is 15 minutes after the question)? Is there any data about this? Did anyone research the issue?