I'd remove the timezone selection from the sign-up / join page. Everything you add to that page that isn't strictly necessary for signing up, is bad for gettin

I'd remove the timezone selection from the sign-up / join page. Everything you add to that page that isn't strictly necessary for signing up, is bad for getting people through the sign-up process. There is nothing critically important about setting the user timezone, for a service like this, such that it must be established on the sign-up page. Place it in a settings section for the user account (if you haven't already) and call it a day.