How to get "Traffic" on StackEgg?

I've graduated my site on StackEgg, and now a new stat called "Traffic" appeared alongside the other four.

However, whatever I do, it doesn't seem to gain hearts.

What am I missing?

The value of traffic goes up or down by a certain amount each day, depending on the displayed value for Quality and Answers:

                      Answers
        |  -1  |   0  |   1  |   2  |   3  |   4  
  ——————+——————+——————+——————+——————+——————+——————
    -1  | -0.8 | -0.8 | -0.8 | -0.5 | -0.4 | -0.2 
Q ——————+——————+——————+——————+——————+——————+——————
u    0  | -0.8 | -0.8 | -0.8 | -0.5 | -0.4 | -0.2 
a ——————+——————+——————+——————+——————+——————+——————
l    1  | -0.8 | -0.8 | -0.8 | -0.5 | -0.4 | -0.2 
i ——————+——————+——————+——————+——————+——————+——————
t    2  | -0.5 | -0.5 | -0.5 | -0.2 | -0.1 |  0.1 
y ——————+——————+——————+——————+——————+——————+——————
     3  | -0.4 | -0.4 | -0.4 | -0.1 |  0.0 |  0.2 
  ——————+——————+——————+——————+——————+——————+——————
     4  | -0.2 | -0.2 | -0.2 |  0.1 |  0.2 |  0.4 

^{-1 means red/critical}

So Answers plus Quality has to be greater than six to at least break even.

From the description of "Answer"

Posting answers is what your Site's life is all about. Only with many answers (and high quality!) can it attract traffic.

• 4 Answer + 4 Quality next Round -> Answer -> Still no traffic
• 2nd Answer -> 1 Traffic

Also not completely true the above the following just happened:

• 3/3/2/3/1 -> Question -> +1 Traffic
• 3/3/2/3/2 -> Question -> +1 Traffic

So Questions can attract traffic too.