Agreed completely. Not showing or telling a first time user in clear, concise language why the $&*% they're on the site is a great way to have a sky high bounce

Agreed completely. Not showing or telling a first time user in clear, concise language why the $&*% they're on the site is a great way to have a sky high bounce rate. If you worry about boring existing users employ tools like "don't show this again" buttons, cookies to know when they're returning users and present them their dashboard(tumblr does this very well) etc but don't alienate first time visitors if you want new users.