Some SEMs suggest buying old domains, then resetting the system clock on your UNIX servers to take the pages look old. Hmm. Sounds a bit too black hat for my liking! In SEO, may looks prefer a lie is a lie! Much better to buy your domain early (before you need to set the business operations) and undertake SEO activities in coming of launch. A bit more you have to have the site to be live and doing business, most within the ageing delay has expired!