People who are running forums, is the CTR really low about how long does it go and how high does it go?
It depends on your new/repeat visitor ratio. Forum pages are just like any other site. However as repeat visitors create too many page impressions, the CTR goes down. Repeat visitors (mostly members) usually do not click ads. New visitors are more likely to clicks ads. I have a forum which gets 150 new and only about 5 repeat visitors each day. I have a CTR in the 2-3% range, which is quite good for a forum.