We've doubled in a month.
We've also gotten more comfortable with our format: @tilikang and I now alternate topics weekly. Each topic is based on a real problem one of us is facing that week.
Talking about real problems has led to regular value to both of us.
Also, we've met some interesting new people who've started listening and / or chiming in.
Another interesting metric:
*32 subscribers (this is a total guess by Transistor)