I was thinking more along the lines of
this typology and personality research. In the typology studied in which they first interviewed 50+ nonbelievers and then had someone code for similarities and differences, they found six different types of nonbelievers:
1) Intellectual Atheist
2) Activist
3) Seeker-Agnostic
4) Anti-Theist
5) Non-Theist
6) Ritual Atheists
You can read the descriptions of each in the link above. I've met people in each of these categories in real life and the internet. What each of these sub-groups has in common is nonbelief in God, but their attitudes towards religion differ, their attitudes about atheism itself differ, and their attitudes about approach differ as well.