Once you set your CNAME record correctly and click Launch you may have to wait up to 72 hours for your page to be live.
The reason for this delay is a process called DNS Propagation which must be finished in order for you page to be visible on the internet. Propagation takes place inside the system of your Internet Service Providers (ISP). As a result, propagation -- and the amount of time it takes -- is beyond the control of LaunchRock.
What is DNS?
DNS stands for Domain Name Server. When you purchase you domain name from your domain registrar they create a Master DNS record in their Domain Name Servers. Your domain registrar then points to your Web Host's DNS server as the master authority of your domain.
When any outside computer wants to know how to find your website, they first go to the domain registration database to find out who the DNS authority is for your website. Then they visit your DNS provider's servers to find out what the IP Address is for your domain name. From there the computer is redirected to your IP on your Web Host's servers and can display your website (it is this point where browsers are redirected to LaunchRock if you have a hosted page).
What is DNS propagation?
To make viewing the web faster for their customers, ISPs cache all of their DNS records. This caching process is called Propagation.
Caching means that the ISPs read and display websites from their local files instead of looking them up on the Internet each time their customers want to view a website. This is similar, on a massive scale, to the way the browser on your computer caches websites to speed up browsing.
Propagation ultimately speeds up web surfing by:
Why does propagation take so long?
The reason it takes so long for your LaunchRock (or any website) to be visible to everyone once you launch it, is that each ISP has an automated process that updates and caches DNS records every few days. Until their cache is reset, it will not display your launched website. There is not any kind of standard for this process, and they can set propagation time anywhere from a few hours up to 72.
Can you speed the process up?
Unfortunately, no. There is nothing that you, LaunchRock or anyone else can do to reduce DNS propagation time. It is simply a case of waiting for this automated process to complete.
Sources: HowStuffWorks Developer Shed Register360