Landing/splash page or content page

I have a crowd-sourced content site. I tend to have a landing/splash page like those Web 2.0 sites, introducing what the site is all about, with screenshots, marketing words, etc. Of course, visitors don't need to be a registered member to make use of the website, since the content is open for public.

I am wondering if I should just show the content of the website from root domain, or use a conventional landing/splash page?

If the landing/splash page is well designed and clear, visitors will benefit. But if it doesn't, it hurts the conversion rate (visitors turn registered members).

Example: Stackoverflow or Stack Exchange sites don't have landing/splash page, it goes straight to content. And thus everyone knows what the site is all about at first glance.

What's your opinion?

Usually people do this because they have no content to show and don't want to waste developing it before finding out if there is any interest. You don't have that problem, so there is no need to mess around with any other alternative. Get started.

If you do, use cookies so that only NEW users see it (you can also use a counter to allow people to get to the splash screen x times and then straight to content). The regular users shouldn't see splash screens of any kind -- just get right to business.