When someone is trying to decide whether your conference might be one they're interested in attending, one of the most important factors is how much it will cost. Most of us have limited travel budgets, and have to spend our pennies carefully.
Consequently, it would behoove you to put the goddam registration fee somewhere on your webpage!
This would be especially helpful for those of us who are trying to put together those aforementioned travel budgets in order to ask for enough money to be able to attend conferences.
Jerkass.
Hugs-n-kisses,
dr_tectonic