I was wondering if the age of the domain is treated differently compared to the age of the site actually being active on the internet.
For example, I have some domain names registered that I plan to use in the future. Is there any advantage to putting up a "placeholder" website on the domain to help its age? Something like:

"Welcome to World of Planets. This site is in the design process and will eventually contain all sorts of information on planets. Thanks for stopping by."

I'm having trouble understanding if the search engines distinguish between when the domain was registered, versus when it was put into active use on the web.