Hi,
I am planning to launch a blog around a topic with domain "example.com". I am using wordpress for the blog. I want to launch an attached forum. Should I go for "www.example.com/forum" or "forum.example.com" in adsense point of view. I know that forums have low CPM and will it affect my blog CPM if I use www.example.com/forum structure? Or should I go for "forum.example.com" so that it will have low CPM and I can maintain my blog at high CPM. Which is the best option?