Merwin: How do You Detect a Bite?

You know the feeling. It's a bite! That little tapping you get as a bass takes a plastic worm. The magic signal of a brook trout chomping a nightcrawler. A striper bumping a plug somewhere in the darkness.

But how do you really sense the taking fish? Rod and line makers spend a lot of money hyping the so-called sensitivity of their products. But as far as fishermen are concerned, that might or might not be money well spent.
Do you feel the bite primarily through the line, for example, or does a sensitive rod give a better message? Some rods have a small portion of the rod blank exposed at the reelseat where--supposedly--you'll have a better feel with a fingertip in contact with the rod. Does that really help?

Maybe you don't feel anything at all, and just detect a bite by watching to see if the line moves or darts. A bobber doesn't count here, by the way, because that's just too obvious.

I'm purposefully not giving my own opinions just yet, because I'd like to know what you think. So you have a bite...but how do you know?