There are many alternatives to WireTap Studio for Mac and since it's discontinued a lot of people are looking for a replacement. The best Mac alternative is Audio Hijack. It's not free, so if you're looking for a free alternative, you could try VB-Audio Virtual Cable or Soundflower. If that doesn't suit you, our users have ranked six alternatives to WireTap Studio and five of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to WireTap Studio are Sound Siphon and Boilsoft Audio Recorder for Mac.
While I don't use Audio Hijack as much as I used to use WireTap Pro, I have set up a couple of ... "sessions," for lack of a better word, to allow me to record audio from web browsers. Great for online radio talkshows or live concerts.
In other words, it takes some getting used to, but you will.