How's retention? In my feeling, when users arrive too fast, then they also go away pretty fast

At first not great, but that was the next lesson to learn. There is always room for improvement but here are some of the latest metrics:

http://cl.ly/image/0P1s321C3a0G http://cl.ly/image/0Z2Y2g041Y0Z

This seems to confirm my thoughts. My read, correctly if I'm wrong, is that after the first 10k, then you probably had to focus back on the product, thus the growth was 0 and possibly most of the 10k were gone (and the reason is usually that the product is ready for 1k, but not for 10k users).

Happy to see that now the growth is solid, thanks for sharing the numbers!

New vs. returning doesn't actually tell you too much about retention unless the growth rate is close to zero, though? Have I got that wrong?

You need a cohort graph to properly illustrate retention.

Once you have their info such as email, you can always remind them, isn't it?

they can put that domain under spam too

This is not a comment on Coderwall, I haven't even looked at it yet. As a developer I've signed up for lots of garbage because it looked interesting. And never went back after the first glance.

A better question, how will you get your first 100 paying customers?